IMPROVEMENTS IN SAFETY BRAKES FOR MINE CAGES, LIFTS AND OTHER LIKE APPARATUS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I JOHN CLAYTON MEWBURN of 169 Fleet Street in the City of London, Fellow
of the Instituto of Patent Agents do hereby declare the nature of my invention for
"IMPROVEMENTS IN SAFETY BRAKES FOR MINE CAGES, LIFTS AND OTHER LIKE
APPARATUS " to be as follows:-
This invention has reference to safety brakes and is specially intended for mine
cages and lifts but it is applicable generally for arresting a rectilinear to and fro
movement whether vertical or otherwise.
The effect of the improved brakes is to efficaciously and immediately grip the
rods or bars which guide the cage or apparatus. They are composed mainly of
striated jaws which can be moved towards or from the guide rods; this movement
is effected by the action of right and left handed screw shafts which are turnéd
by means of racks fixed to the cage and which gear with pinions fixed on the said
shafts. Springs normally keep the jaws open. When owing to the breaking of
the lifting chain or rope the cage falls the racks in descending with it turn the
pinions and threaded shafts and thereby cause the jaws to close upon and grip the
guides. In a modification of the brake, upright rods surrounded by springs which
bear upon the under-side of the cage act upon cross-pieces to which the tails of the
brake jaws are jointed. When the chain breaks the cage in descending produces a
rotation of the right and left handed screw shafts and this causes the jaws to closo
upon and grip the guides.
In another modification the striated jaws have also a movement by which the
friction can be varied at will by adjusting the distance of friction rollers so as to
give more or less grip to the brakes,
"

page_text: COMPLETE SPECIFICATION.
I JOHN CLAYTON MEWBURN of 169 Fleet Street in the City of London, Fellow
of the Institute of Patent Agents do hereby declare the nature of my invention
for "IMPROVEMENTS IN SAFETY BRAKES FOR MINE CAGES, LIFTS AND OTHER LIKE
APPARATUS 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 reference to safety brakes and is specially intended for mine
cages and lifts but it is applicable generally for arresting a rectilinear to and fro
movement whether vertical or otherwise.
The effect of-the-improved brakes when the lifting or hauling chain or ropo
breaks is to efficaciously and immediately grip the rods or bars which-guide-the-
cage or apparatus. They are composed mainly of striated jaws which can be
moved towards or from the guide rods. This movement according to one
modification which is represented in elevation-in-Figure-1-and in plan in Figure
of the annexed drawings is effected by the action of right and left handed screw
'shafts which are turned by means of racks which are fixed to the cage and which
gear with pinions fixed on the said shafts. A is the cage. B, B the shaft or well
of the mine or lift; C, C the guide rods or bars. D, D brackets or stays to keep
the rods C in place. E, E are the jaws of the brakes, they are controlled by the
threaded parts of the right and left handed screw shafts G, G which are mounted
'in. oval holes or slots in arms F, F fixed to the cage. H'H' are racks on the cage
gearing with pinions H, H on the shafts G, G. Springs M normally keep the jaws
.E, E open. When owing to the breaking of the lifting chain or rope the cage falls
the racks H, Hin descending with it turn the pinions H, H and screw shafts G, G
which owing to the oval holes or slots are not forced to fall with the cage; the
jaws E, E are thus caused to close upon and grip the guides C, C. In a modification
of the brake represented in Figures 3 and 4 upright rods L, L surrounded by
springs M, M act upon cross-pieces K, K to which the tails of the brake jaws E, E
are jointed. When the chain breaks the cage in descending produces a rotation of
'the right and left handed screw shafts G, G and this causes the jaws E, E to close
upon and grip the guides C, O.
In another modification represented in Figures 5 and 6 the striated jaws E, E
have also a movement by which the friction can be varied at will by adjusting the
distance of friction rollers so as to give more or less grip to the brakes.
In a further modification represented in front view, side view and plan
respectively in Figures 7, 8 and 9 the cage A has fixed to it a rod R to which
the lifting rope or chain Z is attached; the rod R is provided with a flange a
against which a spring S bears. The cage has guide pieces E, E to work on tho
guide rods or bars C, C. On the flange a bears a frame T-which has guido
pieces U, U to work on the guide rod. To these pieces U, U are jointed the
levers I carrying the striated brake jaws X, X; the fevers are at their other ends

page_text: connected to the cage by the links V, V. In the evont of the rope Z breaking the
spring S comes into action, the cage A is pushed downwards and causes the
levers I, I to turn on their fulcra b, 6 so that the brake jaws X, X are brought
against the rods C, C.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, as communicated to
me, I declare that what I claim is.
The several arrangements substantially as hereinbefore described and reprosented
in the annexed drawings and forming improved safety brakes for mine cages, liſts
and other like apparatus.