Improved Safety Gear for Mining Cages and other Lifts.
Year: 1894

page_text: Date of Application, 16th Jan., 1894
Complete Specification Left, 2th Oct. 1894-Accepted, 24th Nov., 1894
PROVISIONAL SPECIFICATION.
Improved Safety Gear for Mining Cages and other Lifts.
1, SAMUEL ARNOLD of No. 5 Low Row, South Moor, in the County of Durham,
Coal Miner do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide an improved safety gear to be applied
to the cages used in mining shafts and to lifts in general for the purpose of
preventing the fall of such cage or lift in event of the hoisting rope breaking
or other accident occuring whereby the cage loses its support.
I provide on the side of the cage a plate or considerable weight attached to the
cage by bolts passing through vertical slots in the plate or in any other equivalent
manner so that the plate has a limited vertical movement on the side of the cage.
This plate controls by pins and slots or otherwise one or more pairs of pivoted
catchers in such a way that when the plate falls it throws upward the catchers so
that their ends grip against the guide or guides which may be one or more fixed
rails or a wire rope according to the system of guiding employed, the catchers
being also arranged to be thrown inwards or outwards according to the system of
guiding. The ends of the catchers are curved so as to be excentric of the pivots of
the catchers in order that they may grip tightly to the guide under the pressure.
of the weight of the cage.
The sliding plate is held suspended by the boisting rope or equivalent so that on
breaking of the latter the plate falls and causes the catchers to enter into
action.
Dated this 18th da of Tenu 180
COMPLETE SPECIFICATION.
Improved Safety Gear for Mining Cages and other Lifts.
I SAMUEL ARNOLD of No. 5 Low Row, South Moor, in the County of Durham,
Coal Miner, 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 :-
The object of this invention is to provide an improved safety gear to be applied
to the cages used in mining shafts, and to lifts in general for the purpose of
preventing the fall of such cage or lift in event of the hoisting rope breaking or
other accident occurring whereby the cage loses its support.
I provide on the side of the cage a plate or plates of considerable weight
attached to the cage by bolts passing through vertical slots in the plate or in any
other equivalent manner so that the plate has a limited vertical movement on the
side of the cage. This plate controls, by pins and slots or otherwise, one or more
pairs of pivoted catchers in such a way that when the plate falls it throws upward
the catchers so that their ends grip against the guide or guides which may be one
or more fixed rails or bars or wooden beams or a wire rope according to the system of
guiding employed, the catchers being also arranged to be thrown inwards or
outwards according to the system of guiding.
The ends of the catchers are curved so as to be eccentric with regard to the

page_text: pivots of the respective catchers in order that they may grip tightly on the guide
under the pressure of the weight of the cage.
The sliding plate is held suspended by the hoisting rope or equivalent so that on
breaking of the latter the plate falls and causes the catchers to enter into
action.
In the annexed drawings two forms of this improved safety gear are illustrated.
Fig. 1 is a side elevation showing the gear applied to the side of a lift cage
and adapted to lock by outward movement of its catchers against two rails. Fig. 2
is a vertical section and Fig. 3 a horizontal section thereof.
Fig. 4 is a side elevation showing the construction wherein the catchers move
inwards and engage on opposite sides of one guide only, such as a wire rope. Fig. 5
is a vertical section and Fig. 6 a horizontal section of this latter construction.
Referring to Sheet 1, A is the cage or part of cage. P is a plate of iron, steel,
or any other suitable material and of sufficient weight when released to throw the
gripping levers or catchers into their position of engagement. S is a shackle for
connecting the plate P by means of a rope or chain to the main lifting rope or
chain, preferably to the eye, or link or shackle on the end of the lifting rope to
which the cage chains are attached. K are the gripping levers or catches of any
suitable material. These may be smoothed, roughened or toothed on their gripping
surfaces. The gripping or wearing surface is an arc described from a centre below
the centre of the fulcrum B. The catches K are connected to the plate P by bolts
or pins D passing through slots E in plate P. The catches are pivoted on bolts B
fixed or carried on the cage A by the brackets L or other suitable means.
bolts B are of sufficient strength to carry all the strain that may be put on them,
either due to the weight of the cage and its contents or the thrust of the catches K
when gripping. The bolts B are prolonged through vertical slots C in plate P and
thus act as guides to the plate when it is rising or falling independently of the cage.
The slots E are shaped vertically or otherwise at their lower ends to allow the
catches K to rise and fall through an angle sufficient to remain clear of the
guides M when not in action. This position of the catches is shown in dotted
lines in Fig. 1.
The
When the plate P falls far enough to bring the pins D into the upper
iuward bends of the slots E, the catches K pass into the gripping position
shown in full lines.
Fig 1 shows an arrangement of guides M often used in collieries, but the
arrangement may be modified to suit corner guides. Sheet 2, shows the application
to a central rope guide. To suit the rope the gripping edges of the catches K
are slightly hollowed; this arrangement will suit any section of central or middle
guide, and may be also modified to suit four or more rope guides. The plate P is
made in two or more pieces connected by joint strips Q.
The action of the invention is as follows:-The length of the chain or rope
connecting the shackle S to the main lifting rope being shorter than the cage
chains, the plate P will be lifted through a certain distance when or before the cage
chains become tight, that is the plate will rise before the cage. The catches K
being pivoted on the cage at B and connected to the plate P by the pins D will,
when the plate rises, be drawn off the guides M into the position shown by dotted
lines and this position will be maintained so long as the lifting rope is kept tight.
Should the lifting rope break, then under the action of gravity, the whole weight
of the plate will act on pins D simultaneously, and all the catches K will be forced
against the guides M. D being at a higher elevation than 13, a wedge action will be
set up and all the strain being taken by the bolts B, which are rigidly connected
to the cage, the latter will be stopped from falling.
In a colliery shaft or any other kind of hoistway the air offers a very decided
resistance to the falling of a large body with a large exposed surface like the cage,
whereas the weighted plate which offers a comparatively very small surface to this
resistance of the air, falls very freely. The breakage of the rope generally occurs
when the cage is being lifted, and the cage for an instant is at rest; the plate also
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page_text: is at rest, but its inertia seems to be sooner overcome than that of the cage and
almost before the latter moves, the catch pieces are thrown into action by the plate,
and the whole is held.
The heavy or weighted plate does away with the necessity for springs and is so
connected to the cage and catch pieces, that when the lifting rope breaks, all the
catches are thrown into action simultaneously and with equal force.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination, with a lift cage of a weighty plate or plates connected to be
raised upon the lift cage previously to the latter being lifted and connected to
pivoted gripping pieces in such a manner that a fall of the plate or plates upon the
lift cage moves the gripping pieces into engagement with the guide or guides.
without intervention of springs substantially as described.
2. The construction of plate or plates P with slots for its guidance and for the
operation of pivoted gripping pieces K substantially as illustrated and described.
R. HADDAN,
Of the Firm of Herbert Haddan & Co.,
18, Buckingham Street, Strand, London, W.C.,
Agent for the Applicant.