Improvements in Safety-mechanism for Hoists, Lifts, and the like.
Year: 1893

page_text: Date of Application; 20th Feb., 1893
Complete Specification Left, 8th Dec., 1893-Accepted, 20th Jan, 1894
PROVISIONAL SPECIFICATION.
Improvements in Safety-mechanism for Hoists, Lifts, and the like.
A communication from JULES DES GEORGES, of Paris, in the French Republic,
Machine Builder and Engineer.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent do hereby declare the nature of this invention to be as
follows:-
The object of this safety-mechanism is to prevent falls and accidents due to the
breaking of the cable or chain.
The cage has its uprights provided at a suitable height and adjacent to the
guiding uprights with guide blocks in which are free to slide wedge shaped
shoes fitted by dove-tail projections in corresponding grooves in the sides of the
blocks and acting as wedges in conjunction with those sides, where they come into
frictional contact with them; the inner and diametrically opposite faces of these
shoes are vertical and fit against the guiding uprights.
The cable or chain supporting the cage is preferably attached to a pivotted
frame the pivot serving as a point of support for the cross-piece of the cage.
Upon the lower portion of this frame are arranged to bear the longer arms of
two levers the shorter arms being adapted to force back the wedge-shaped shoes,
which, in sliding in the dove-tail grooves of their cases or guides compress springs
and take up such a position that their vertical or operating surfaces, acting upon
the guiding-uprights are situated at a distance of about 3 millimetres from the said
uprights. Thus the brake under normal circumstances remains inoperative both in
the upward and downward movements of the cage or lift, which consequently
travels freely and unimpeded. Should however, the cable or chain break, the
space left free at the upper part of the frame between the cross-piece and 'the point
of attachment of the cable, enables the said frame to descend, and release the
levers. These levers being free, their shorter arms no longer bear upon the shoes
which under the action of their springs are forced further into or through their
guide blocks and by reason of their wedge form are jammed against the guiding
uprights and prevent the cage from falling.
The frictional effect of these brake-shoes may be considerably increased, if
necessary, by making their surfaces rough, or serrating or grooving them, the effect
produced being in all cases an instantaneous stoppage of the cage, lift, basket, or the
like, and the effectual prevention of accident.
The details of the arrangements herein described may, of course, vary according
to the particular purpose for which they are employed.
Dated this 20th day of February 1893.

page_text: A communication from JULES DES GEORGES, of Paris, in the Republic of France,
Machine Builder and Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent 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 relates to lifts and other apparatus for raising weights and has
for its object the construction of a safety device for preventing the dropping of the
cage of the lift or similar apparatus in case of the breaking or parting of the cable
or chain.
In the annexed drawings the safety device is illustrated.
Fig. 1 shows the cage of a lift provided with the safety device in front
elevation.
Fig. 2 is a side view of the safety device alone, partly in section and on an
enlarged scale.
Fig. 3 is a plan-view of the safety device corresponding to Fig. 2.
In all figures similar letters of reference indicate corresponding parts.
In the elevator cage A the standards B are at convenient height and parallel
to the clevator guides C provided with projections D in form of sleeves or slides
for the brakeshoes E which are guided in sleeves or boxes D in dove-tail
grooves. Parts E are wedge-shaped and the guides in sleeves D in which they
run, are of corresponding form while the opposite face of parts E adjoining guide
post C runs parallel to the latter. The cable or chain F which supports the cage
is attached to a strap or shackle G provided with a pin H upon which rests the
cross beam I of cage A.
Upon the lower part of strap G at J rests two levers K each swinging upon a
pivot L. As long as the weight of the cage is supported by its cable, strap G
keeps levers K in a raised position whereby their outside ends or heads M are
pressed down upon the shoes or wedges E, in such manner as to compress
springs N, thereby bringing wedges E in such position that their vertical or
operative surfaces stand removed from guide-posts C at a distance of about
one eighth inch. In this position the brake does not interfere with the regular
operation of the lift or elevator and rests inactive in the ascent as well as in
the descent of the apparatus. In case however of the breaking of the cable or
chain, the play which shackle G has in its upper part at O between cross beam I
and place P where it is attached to the chain or. cable, permits the dropping of
shackle G whereby its pressure against levers K ceases and the latter become free.
As soon as the pressure of the ends or heads M of these levers K ceases to be
exerted upon wedges E the latter are pushed into boxes D by their springs, which
were compressed before the dropping of shackle G and consequently these wedges E
will jam against or grip guide-posts C.
By this jamming or gripping the tenacity of which, if desired, could still be
considerably increased by roughing the operative surfaces of wedges E an
immediate stopping of the cage is secured, which cannot descend any further,
and whereby every accident is prevented. The constructive details of the
described device may of course be altered without departing from the spirit of
my invention.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner the
same is to be performed, I declare that what I claim is :-
1. In lifts and similar apparatus the combination with the guide rods thereof
of sleeves D attached to the cage of the lift and shoes or wedges such as E
having their outer edges wedge-shaped and guided in the sleeves D and their
inner edges parallel and in close proximity to the guide rods; substantially as
described.
2. In lifts and similar apparatus the combination with the guide rod sleeves D
attached to the cage of the lift and shoes or wedges E having their outer edges
wedge-shaped and guided in sleeves D and their inner edges parallel and in close
proximity to the guide rods of springs such as N tending to jam the wedges E
against the guide rods; substantially as described.
3. In lifts and similar apparatus the combination with the guide rod sleeves D
attached to the cage of the lift and shoes or wedges E having their outer edges
wedge-shaped and guided in sleeves D and their inner edges parallel and in
close proximity to the guide rods of springs N tending to jam wedges E against
the guide rods and levers such as K operated by the weight of the cage when
suspended to its cable or chain so as to compress springs N; substantially as
described.
1
1000
W. P. THOMPSON & BOULT,
Of London, Liverpool, Nottingham, and Manchester,
Agents for the Applicant.