Improvements in Self-acting Brakes for Lifts.
Year: 1893

page_text: Date of Application, 25th July, 1893-Accepted, 2nd Sept., 1893
COMPLETE SPECIFICATION.
Improvements in Self-acting Brakes for Lifts.
I, GEORG WILHELM LUDOVICI, of 27 Grüner Weg, Cassel, in the Empire of
Germany, Locksmith, do hereby declare the nature of my said invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The object of my invention is to fit lifts with improved double self-acting safety
brakes; the brakes being independent of each other.
And in order that my said invention may be particularly described and ascer-
tained, reference is hereby made to the accompanying drawings, in which similar
letters of reference indicate corresponding parts.
Fig. 1 is an elevation of a lift fitted with my improvements, the ropes being
shown intact, and the brakes out of action.
Fig. 2 is a side view of Fig. 1.
Fig. 3 is an elevation, partly in section, showing the brakes in operation.
The lift is formed in two parts, consisting of a frame a, running in guides hh,
and the cage b, which is capable of sliding a short distance in the frame a; the
guides being shown in section in Fig. 1, but other forms of guides may be used, if
preferred. The brake mechanisms are shown fitted to both ends of the frame a,
above and below.
The upper brake mechanism consists of two levers cc, pivoted to the frame a
at d d. gg are two wedge shaped brake blocks, with serrated contact surfaces,
pivoted at ii to the short arms of the levers c c. oo are weights fitted to the long
arms of the levers c c. kk are springs, one end of each spring being attached to
the frame a, and the other end to the lever c, as shown. The object of the weight o
and spring k is to render the operation of the brake sure, so that, in case the
spring k should jump, the weight would cause the lever to apply the brake. In
ordinary cases the springs and weights o operate together. jj are wedges formed
in the frame a, which hold the brake blocks g in position pressing them against the
framesh, when raised by the short arms of the levers c c.
pp..
The lower brake consists of two levers ll, pivoted to the frame a at
m m are two wedge-shaped brake blocks, pivoted at ss to the short arms of the
levers 1 l. nn are wedges formed in the frame a to hold the brake blocks m in
position, when raised by the short arms of the levers 11. The long arms of the
levers are in contact with a portion of the frame b of the cage, the position
being secured by contact with the plates under the floor of the cage, or by other
suitable means.
The lift is sustained by two forked straps ff, through which the levers c c pass..
ee are two pins, which lift the levers c when the cage is sustained by the straps ff..
Each strap carries a loose pulley at its upper end for receiving the rope.
The operation is as follows:-When the lift is sustained by ropes or cords as
shown in Fig. 1, the head of the frame of the cage b is raised into contact with the
upper part of a. The pins e e lift the long arms of the levers cc, and thereby
withdraw the brake blocks g g from contact with the guide bars h. In like
manner the raising of the frame b in the frame a, lifts the long arms of the levers 1 l,.
the brake blocks m m being thereby withdrawn from contact with the guide bars h h..
The lift is thus free to be raised or lowered.
On the breaking of one or more rope or ropes, as shown in Fig. 3, or the sudden
fall of the lift, the supports ff are released, the long arms of the levers c c and l
are then depressed by the weights o o, springs kk, and lowering of the frame b,
whereby the wedges g g and m m are jammed between the wedges j and n and the
guides hh, whereby the motion of the lift is immediately arrested.

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Should the lift be again raised, all the wedges are immediately released, and the
lift is free.
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 lift, the combination of an outer frame a, an inner frame b, brackets or
straps ff, levers cc, wedges 9 9 and jj, weights oo and springs kk, for extending
the lever arms and operating the wedges gg, on the breaking of a rope or sudden
fall of the lift; all severally operating substantially as herein before described and
illustrated by the drawings.
2. In a lift, the combination of an outer frame a, an inner frame b, brackets or
straps ff, levers 11, and wedges mm and nn; the positions of the levers and
wedges being governed by the relative positions of the frames a and b, all severally
operating substantially as and for the purposes herein before described and
illustrated by the drawings.
3. In a lift, the combination of the independent brake mechanisms claimed in the
first and second claims, substantially as and for the purposes described and
illustrated by the drawings.
4. The general construction, arrangement, and combination of the several and
respective parts, together forming my invention of improvements in self-acting
brakes for lifts, substantially as herein before described and illustrated by the
drawings.
GEO.
DOWNING,
8, Quality Court, London, W.C., Agent.