An Improved Brake Coupling or Clutch for Hoisting Apparatuses.
Year: 1897

page_text: Date of Application, 8th May, 1897-Accepted, 26th June, 1897
COMPLETE SPECIFICATION.
An Improved Brake Coupling or Clutch for Hoisting Apparatuses.
I, ANTON BOLZANI of 91, 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 a brake device for hoisting apparatus which by
the introduction of a new means is rendered as simple as possible in its parts and
yet yields an exact and easy braking action on the descent of the load with smallest
expenditure of power and yet with complete safety and certainty.
The arrangement is shown in the accompanying drawings, in which :-
Figures 1 and 2 are longitudinal and transverse sections of a form of construction
with movable brake ring held against rotation in one direction.
Figures 3 and 4 are similar views of a second form of construction with a fixed
brake ring without a stop device.
A third form of construction is shown in Figures 5 and 6, whilst,
Figures 7 and 8 show separately the cam loosely.mounted on the spindle.
Clutches d
g
An
hare
a is the spindle or shaft to be braked, on which the nave of the driving
mechanism (hand wheel, crank or the like) is loosely revolubly mounted. c is a
disc firmly connected with the spindle or made in one piece with it.
and e are arranged on said disc and on the nave of the driving mechanism.
eccentric is also loosely mounted on the spindle and two brake shoes
mounted to slide on the cylindrical surface of this eccentric. The whole is
enclosed by a brake ring i having ratchet teeth i, in which a pawl k engages and
only allows the ring to revolve in the direction of the arrow, that is, in the lifting
direction. The clutches & firmly connected with the shaft grip the brake shoe h
A direct
between them, whilst the brake shoe g is gripped by the clutches e.
action of the operating mechanism can therefore only be exerted on the brake
shoe
whilst the load can only act directly on the brake shoe h. The brake shoes
occupy the space between the cylindrical surface of the eccentric fand the inner
surface of the brake ring i, lying concentrically to the spindle a; they are
therefore similar in form to curved wedges.
If the hand chain wheel or the like be revolved in the lifting direction (direction
of the arrow), the brake shoe g will be moved in the direction of the arrow by
means of the clutch e, and pressed into the narrowing space between the eccentric f
and brake ring i. As however the eccentric is mounted loosely on the spindle a
it will rotate a little until the shoe also exerts the same brake pressure against
the brake ring as the shoe J. If this pressure be sufficiently great a firm coupling
between all parts will be established and the spindle will be turned in the lifting
direction by means of the clutch d, that is to say, the load will be hoisted.
the movement ceasing, this condition of the coupling will remain and the load be
maintained in its position as the brake ring cannot turn backwards in consequence
of its ratchet teeth and the pawl engaging therein.
21
Ou
If the driving mechanisin be brought into the opposite direction, that is, the
lowering direction, the brake shoe will be moved towards the other part of the
space between the eccentric fand brake ring i, and the loosely mounted eccentric,
in consequence of the friction, will be carried somewhat with it, so that the shoe
also undergoes a slighter brake pressure than before. The braking is therefore

page_text: :
diminished and the load can descend as long as the brake shoe g continues to be
moved in a descending direction. If this movement ceases, the load will move the
brake shoe further in a descending direction until, by means of the loose eccentric,
the brake pressure necessary for bringing it to a standstill is again attained. An
unintentional dropping of the load is thus impossible but on the contrary it is only
possible to produce a lowering of the load by operating the driving mechanism to a
corresponding extent.
In the form of construction shown in Figures 3 and 4, instead of a brake ring
held against rotation in one direction, a brake ring is employed firmly connected
with the frame,
The further modification of the arrangement consists of the following
The load by means of a clutch m, mounted on the disc c, acts directly on the
brake shoe as before, whilst a clutch n is connected with the driving mechanism
and can act both on the brake shoe hand also on the brake shoe g, according as it
is desired to hoist or lower. In the first case, the brake shoe is moved in the
direction of the arrow by means of the hand chain wheel or the like and the
clutch n, so that the brake pressure is taken off and as the clutch m also presses against
the shoe , the shaft is revolved in a lifting direction by means of this shoe by the
intermediary of the clutch, and the load is hoisted. When the hoisting movement
ceases and the driving mechanism is released, a small retrograde motion of the
shoe in a descending direction takes place by means of the load, until, by the
intermediary of the loose eccentric, the brake pressure between both shoes and
the brake ring is so great that the load is rendered stationary. When the load is
to be lowered, the driving mechanism is revolved in an opposite direction to the
lifting direction, so that the clutch n bears on the brake shoe g, as shown in dotted
lines. On further rotation, the shoe is loosened, consequently the brake pressure
of both jaws against the brake ring is diminished, so that the lowering of the load
can take place. In this form of construction therefore, both in raising and lowering,
the brake pressure is diminished, whilst in the first form of construction this is only
the case in lowering.
In order to avoid rotating the eccentric when revolving the unloaded hoisting
degice in a lowering direction, a clutch or a projection o is combined with the
eccentric, so as to engage in the interval between the brake shoes and g so that
the correct position of the eccentric, between them always remains assured.
In the third form of construction, shown in Figures 5-7, pressure is exerted
by the brake shoes gh not only against the inner cylindrical surface of the brake
ring but also against a disc i connected therewith. For this object the loose
eccentric is formed as a double eccentric or stepped cam, so that each of its
eccentric surfaces acts on one of the shoes gh. It is also screw-threaded internally
and by this means travels on a screw thread a' formed on the shaft, so that it
undergoes together with its rotation an axial displacement. In order to exert
an axial pressure on the brake jaws during this displacement, it is provided with
a flange
If therefore the driving mechanism be moved in the direction of the arrow,
the clutches p of the same act on the two shoes g and h.
surfaces of the brake shoes in this form of construction
the loose cam is also revolved in the direction of the
displaced in the direction of the collar c so far until a
the plane surfaces of the brake shoes 9 and h, the disc
the collar c takes place.
с
As however the wedge
have the same direction,
arrow, it being axially
certain pressure between
of the brake ring i and
The brake shoes g and then adjust themselves on the eccentric surfaces of
the cam so much that the necessary friction is produced even on their cylindrical
outer surfaces and a thorough coupling of all parts with the brake ring is effected,
the shaft is revolved and thus the load is raised. If this lifting motion cease
the pawl prevents any retrograding or sinking of the load. Only when the
driving mechanism is rotated in a direction opposite to that indicated by the
arrow, does there take place a retrograde movement of the brake shoes
and h
g

page_text: that is to say, a diminution of the brake pressure on the cylindrical surfaces.
The eccentric body or cam is however at the same time carried somewhat along
with it, that is to say, turned backwards and consequently also the pressure ou
the plane surfaces somewhat diminished. If this diminution of pressure be great
enough, the load will descend as long as the operating mechanism is moved
forward in the same direction.
If the lowering movement of the driving mechanism cease, the load again
causes, through the shaft, an axial adjustment of the loose eccentric or cam
towards the collar c and as the brake shoes thereby undergo friction on the plane
surfaces they remain behind, so that the eccentric body or cam moves forward.
a little further beneath them and consequently causes an increase of the radial
pressure until a complete stoppage is 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. A brake coupling or clutch for hoisting apparatuses, characterised by two
curved wedge picces being arranged to slide with their outer surfaces on the
inner surface of a brake ring and their inner surfaces on a loose cylindrical
body mounted eccentrically to the shaft, whilst the load and the driving mechanism
engage directly on the wedge pieces by means of clutches substantially as herein-
before set forth.
2. A brake coupling or clutch for hoisting apparatuses such as described,
characterised by the brake ring, owing to the action of ratchet teeth and a
pawl engaging therein, being only revoluble in the hoisting direction, and by the
one wedge piece being directly connected with the shaft only, and the other
directly with the driving mechanism only, so that when hoisting, all the parts
are coupled or clutched, whilst on lowering, a movement with a diminution of
the frictional pressure of the brake surfaces takes place, substantially as described.
3. A brake coupling or clutch for hoisting apparatuses such as described,
characterised by the brake ring being rigidly mounted and by the load tending
to displace one wedge-piece in such a way that a braking effect is produced,
whilst the driving mechanism, when lifting, acts by means of a clutch, upon the
wedge piece on which the load acts, and, when lowering, acts on the other wedge-
piece, in each case pushing the same back so that a diminution of the brake
pressure takes place and movement is permitted, substantially as described.
4. A brake coupling or clutch for hoisting apparatuses such as described,
characterised by the brake ring, which is retained in the descending direction,
having an inner flange which rests between a fixed collar on the shaft and the
wedge pieces, and by the loose eccentric body being formed as a stepped cam
or with two eccentric surfaces set at an angle of 180° to each other and each
acting on a wedge piece, said eccentric body being mounted with a screw thread
on the shaft in such a way that when hoisting, the wedge pieces are pressed,
by means of a flange arranged on the eccentric, against the inner flange of the
brake ring which in turn is pressed against the fixed collar of the shaft, the
driving mechanism alone carrying clutches to act on the wedge pieces, substantially
as described.
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.