IMPROVEMENTS IN BRAKE MECHANISM FOR HOISTING APPARATUS to be as follows:
Year: 1885

page_text: I, GEORG MEHLIS, Engineer, of the firm of Maschinenfabrik Cyclop Mehlis &
Behrens at Berlin, Pankstrasse, Germany do hereby declare the nature of my
invention for "IMPROVEMENTS IN BRAKE MECHANISM FOR HOISTING APPARATUS
to be as follows:-
"
This invention relates to improved brake-mechanism for hoisting apparatus,
which brake-mechanism, as compared with other mechanism of this class, is
characterized by the employment of a friction-drum for stopping the apparatus
when the crank, or the lifting chain or rope, is released; the said friction-drum
being secured upon a separate shaft, carrying ratchet mechanism; and supporting,
by means of a friction-strap or band, one end of the lifting chain.
In applying the present invention to a winch, one end of the load chain is
attached to the winding drum, and the other end is suspended from a friction-
strap or band which is placed around a friction-drum fixed upon a shaft hereinafter
termed the brake-shaft. The load is lifted by a hook connected with a loose pulley
running in the bight of the rope or chain.
In order to at once stop the load when the winding crank is released, the brake-
shaft is connected with the winch by suitable gearing. A pinion upon the crank-
shaft drives a gear wheel upon an intermediate shaft. A second pinion upon this
latter shaft drives a second gear wheel on the drum,
Another pinion on the intermediate shaft, hereinafter termed the third pinion,
drives a third gear-wheel on the brake shaft. The latter gear-wheel turns loosely
upon its shaft when a load is being lifted, and, in this case, ratchet teeth formed
upon the said third gear-wheel slide freely below ratchet-pawls carried on a disc
mounted on the intermediate shaft. The ratchet-pawls are kept in contact with
the ratchet teeth of the third gear wheel by springs.
The gearing for coupling the brake shaft with the crank shaft can be replaced by
chains and chain-wheels.
By reason of the arrangement described, the brake-shaft remains stationary when
a load is being raised. If now, the winding crank is released the load, through the
medium of the gearing described, tends to move the ratchet teeth of the third
gear wheel in an opposite direction to that in which they were previously moving,
so that they engage with the pawls upon the disc.

page_text: As the brake shaft is continually subjected to the weight of the load it is
generally prevented from turning. As the brake pressure increases proportionally
to the load, nothing is changed in the action of the winch whether the load be
great or small. The tendency to move back produced by the load is, in all cases,
counteracted by the load itself.
If the load is to be lowered, it is necessary to turn the crank in a backward
direction. In this motion the brake shaft is also turned, overcoming the friction
exerted by the friction strap or band upon the brake drum.
In applying the improved mechanism to hoisting tackle the brake drum is
arranged directly upon the axis of the driving-chain pulley. The teeth of a pinion
upon the said axis are surrounded by an annular casing, attached to, or integral
with, the friction drum which turns upon a fixed collar in the side plates of the
tackle, and upon which bears the friction strap or band to which one end of the
lifting chain is attached. Between the teeth of this pinion and the interior of
the said annular casing are four rollers or halls. These rollers or balls enable a
free revolution of the said axis in one direction, say from right to left. The said
pinion engages with a gear wheel over the shaft of which the lifting chain passes.
If now, the driving chain pulley is moved from right to left the lifting chain
wheel is turned, thereby raising the load.
If the driving chain is released, the load turns the pinion in the opposite
direction to that described, until the said rollers or balls are nipped between the
teeth of the said pinion and the casing attached to the friction drum, and as the
latter is held by the friction of the strap or band to which one end of the lifting
chain is attached the load is prevented from running down.
This automatic brake mechanism can be applied to other forms of hoisting
apparatus than these described, the arrangement of the connecting gearing inserted
between the brake shaft, and the driving shaft being varied to suit the different
forms of apparatus.

page_text: Figures 4, 5, and 6 are views of details, drawn to an enlarged scale.
Figures 7, 8 and 9 are sectional views showing the application of the improved
brake-mechanism to a pulley block.
As shown in figure 1, one end a of the lifting chain is attached to the winding
drum, and the other end 6 is suspended from a friction-strap or band c which is
placed around a friction drum e fixed upon a shaft d.
f is a pulley which runs in the bight of the chain, and which carries a hook for
supporting the load.
g is a crank handle by which the winding drum is rotated
through the medium of suitable gearing.
In order to at once stop the load when the crank g is released, the brake-shaft d
is connected with the winch by suitable gearing. The pinion 1 upon the crank-
shaft engages with a gear-wheel 2 upon the intermediate shaft h, and a pinion 3
upon the shaft h engages with the gear-wheel 4 on the shaft of the winding drum.
A second pinion 5 on the intermediate shaft h engages with the gear-wheel 6 on
the brake-shaft d, and turns loosely upon the latter when a, load is being lifted.
Upon one side of the gear-wheel 6 is formed a series of ratchet teeth, and upon
the shaft d is fixed a disc s having the ratchet-pawls engaging with said ratchet
teeth as shown in Figure 6. The ratchet-pawls are kept in contact with the
ratchet teeth of the gear-wheel 6 by springs.
The gearing for coupling the brake-shaft d with the crank-shaft can be replaced
by chains and chain-wheels.
By reason of the arrangement described, the brake-shaft d remains stationary
when the load is being raised, the pawls sliding over the ratchet teeth. If, now,
the crank g is released, the load, through the medium of the gearing described,
tends to move the gear-wheel 6 having ratchet teeth z in an opposite direction to
that in which it was previously noving, so that the said teeth engage with the
pawls k upon the disc 8. As the brake-shaft d is continually subjected to the
weight of the load it is generally prevented from turning. As the brake-pressure

page_text: increases proportionally to the load, nothing is changed in the action of the winch
whether the load be great or small, the tendency to move back produced by the
load, being in all cases counteracted by the load itself.
If the load is to be lowered, it is necessary to turn the crank in a backward
direction. In this motion the brake-shaft d is also turned, overcoming the friction
exerted by the brake friction strap or band c upon the brake drum e.
Figures 7 to 9 show the application of my improvements to hoisting tackle.
In this modification the brake drum n is arranged directly upon the shaft o of
the driving-chain pulley 1, and is surrounded by the strap n¹ to which one end u
of the lifting chain is connected. The other end u¹ of said chain passes over the
chain wheel formed integral with the gear-wheel r and supported on the shaft w.
The pinion m on the shaft o, engages with the pinion r, and has, at one end, the
inclined teeth m². The said teeth m' are surrounded by an annular extension of
the friction-drum n, which latter turns upon the fixed collary.
Between the teeth m¹ and the interior of the said annular extension are four
rollers or balls k. These rollers or balls allow a free revolution of the shaft o in
the direction indicated by the arrow, figure 7, the said rollers or balls being
carried round by the teeth m¹.
If, however, the chain passing over the driving pulley is released, the load
turns the pinion m having the teeth m¹ in the opposite direction' to that indicated
by the arrow, whereby the said rollers or balls kare nipped or jammed between
the teeth m' and the extension of the friction-drum n. As the latter is held by
the friction of the strap or band n¹ to which one end u of the lifting chain is
attached the load is prevented from running down.
This automatic brake-mechanism can be applied to other forms of hoisting
apparatus than those described, the arrangement of the connecting gearing inserted
between the brake shaft and the driving shaft being varied to suit the different
forms of apparatus.
:
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
In automatic brake-mechanism for hoisting apparatus, the employment of a
ratchet wheel, or its equivalent, in combination with a friction drum and a friction
strap or band to which one end of the lifting rope or chain is connected, the said
rope or chain being passed over one or more pulleys, and the ratchet-wheel or its
equivalent connected with the gearing of the hoisting apparatus in such a manner,
that, when the load is lifted, the hoisting mechanism can rotate without the friction.
drum turning with it, whilst when the load descends, the brake drum must
participate in the rotation of the said mechanism.
Dated thig 12th dow of Mov 1886
HASELTINE, LAKE & Co.,
Agents for the Applicant.