Improved Brake for Hoisting Apparatus.
Year: 1896

page_text: Date of Application, 26th June, 1896-Accepted, 19th Sept., 1896
COMPLETE SPECIFICATION.
Improved Brake for Hoisting 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 a brake for hoisting apparatus which must be
regarded as a considerable advance in the domain of hoisting appliances, as by the use
of this improved brake not only is the handling of the hoisting device simplified but
the security of working, that is to say, security in braking the raised load is increased
to the highest imaginable extent.
The arrangement is shown in the accompanying drawings, Figure 1 being a vertical
longitudinal section, Figure 2 an end view and Figure 3 a partial section of a
somewhat modified form of construction.
As may be seen from the drawings a laterally flanged disc or cylindrical sleeve b
open at one end is revolubly mounted on the hoisting shaft a to which the manual or
machine (mechanical) power is applied, which sleeve is prevented from revolving in a
descending direction by means of ratchet teeth and pawl c or by means of any
other suitable device fulfilling the same object. The open end of this sleeve is closed
by a disc d having spurs or projections d which engage in longitudinal grooves or
slots 62 in the sleeve b whereby said disc may be longitudinally adjusted against the
sleeve but must follow its movement of rotation. The end of the shaft a projecting
out of the sleeve and passing through the disc d, is threaded to receive a crank handle e
or hand wheel, belt pulley, cog wheel or the like, the nave e¹ of such machine element
bearing against the disc d. A nut is provided for preventing the crank or the like
from turning off the threaded end of the shaft.
Within the sleeve there is also the following arrangement :-
Two discs hand h' are mounted on the shaft a by means of splines 9 or other
suitable means in such a way as not to be revoluble on the shaft but to be
longitudinally adjustable thereon. These discs bear on one side against the end 63 of
the sleeve and at the other side against the disc d, a spiral spring i preferably of
quadratic or rectangular section being inserted between the two discs.
Between the end 6 and the disc h and also between the disc and the disc d,
washers of leather or the like material may be arranged in order to increase the
friction. The surfaces which come in contact need not be plane ones but may have a
conical or other suitable form. The nut f may also be arranged as a set nut on an
extension of the shaft said extension having a screw-thread of opposite pitch to the
thread engaged by the crank so as to enable any desired brake pressure to be fixed by
adjusting the nut to vary the travel of the crank and to regulate the tension of the
spring i.
If a load is to be lifted, the crank handle or hand wheel is first screwed against the
disc d and the spring i is thereby so strongly compressed that the friction between
the frictional surfaces becomes so great that the shaft is carried with them and the
load is raised. If the crank handle be then released, the load remains suspended in its
raised position as the brake pressure does not diminish and the sleeve is prevented by
the pawl from revolving backwards.
If it be desired to lower the load, the crank is turned backwards whereby the brake
pressure between the friction surfaces is diminished as the crank is screwed off the
shaft until movement between the surfaces, that is to say a descent of the load, takes

page_text: place. This backward movement of the shaft a would however, on the stoppage of
the crank, immediately again cause a braking action, as the crank nave finds frictional
resistance on the face of the disc d, whereby it is braked, and caused to lag back so
that the shaft screws itself into the same and thereby increases the brake pressure
which increases until the load is rendered entirely stationary.
If therefore it be desired to continuously lower the load the crank must be
continuously turned backwards, and, as a point of pressure may always be obtained at
which the load just descends, a balance is, to a certain extent, continuously maintained
with the load and it is not necessary, as in other brake devices which afford an equal
security, to overcome an additional brake resistance, as the crank allows itself to be
easily moved in the descending direction behind the descending load.
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 for hoisting apparatus, characterised by discs which are mounted on the
hoisting shaft so as to be not revoluble but longitudinally adjustable thereon and
which are pressed apart by means of a spring, being pressed against other discs which
are loosely mounted on the said shaft and prevented from rotating in a backward
or descending direction by means of a pawl or the like, by the driving mechanism
(crank, handwheel, belt pulley or the like) being mounted on a screw-thread on said
shaft so that on being rotated in a hoisting or lifting direction the said driving
mechanism will bear against one of the loosely mounted discs whilst the other of these
discs which is farthest removed from the crank will bear against a shoulder of the
shaft, the frictional surfaces being of any suitable kind, substantially as hereinbefore
described.
2. A brake for hoisting apparatus such as described in Claim 1 characterised by a
counter nut being arranged to prevent the driving mechanism from being screwed off
the shaft on the shaft being turned backwards, which nut may also be arranged as a
set nut on an extension of the shaft with an opposite pitched thread in order to
produce continuously any desired brake pressure during the lowering or descent of
the load, substantially as described.
3. A brake for hoisting apparatus such as described in Claims 1 and 2 characterised
by the brake discs being so arranged in a sleeve having a solid or closed end bearing
against a shoulder of the shaft that they can slide by means of projections in
longitudinal grooves or slots in said sleeve, substantially as described.
Dated this 25th day of June 1896.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicant.