IMPROVEMENTS IN SAFETY APPARATUS FOR MINE CAGES, HOISTS, AND THE LIKE
Year: 1878

page_text: LETTERS PATENT to John McKellar Main, of Crossfield Iron Ore Works, in the
County of Cumberland, Engincer, for the Invention of "IMPROVEMENTS IN
SAFETY APPARATUS FOR MINE CAGES, HOISTS, AND THE LIKE.”
"
Sealed the 24th December 1878, and dated the 8th July 1878.
PROVISIONAL SPECIFICATION left by the said John McKellar Main at the
Office of the Commissioners of Patents on the 8th July 1878.
JOHN MCKELLAR MAIN, of Crossfield Iron Ore Works, in the County of Cumber-
land, Engineer. "IMPROVEMENTS IN SAFETY. APPARATUS FOR MINE CAGES, HOISTS,
AND THE LIKE.
"
This Invention has for its object to improve the construction and operation of
safety apparatus applied to mine cages, hoists, and the like.
The first part of the Invention relates to the prevention of the descent of the
cage or hoist in the event of the winding or hoisting rope breaking, and the
improved apparatus comprises certain toothed or cross-grooved metal blocks carried
by the cage or hoist, and arranged so as on the rope breaking to grip the wooden
guides usually fixed at the sides of the pit or other place, and between which the
cage or hoist ascends and descends. There are a pair of the gripping blocks for
each fixed guide, and each block is wedge shaped in side view, the bottom being
the broader end. The outer inclined sides of the blocks are fitted. to work in
strong inclined guide cheeks fixed to the framing of the cage or hoist, and are kept
in contact with such cheeks, so that each block is quite clear of the fixed wooden
guide, when at the lower part of its guide cheek, but is wedged against the wooden
guide when at the upper part of its guide cheek. The four gripping blocks are
suspended by chains from pulleys or levers on two horizontal rocking shafts carried
in the upper part of the framing of the cage or hoist, and these rocking shafts have
levers fixed on their middles, to which levers there are jointed the lower ends of
rods fixed at their upper ends to a cross head, to which last the winding or hoisting
rope is attached.

page_text: Between the rocking shaft levers and the top plate of the cage or hoist framing
there are placed on the rods jointed to those levers rubber or other springs, which
are compressed by the weight of the cage or hoist when it is depending from the
rope, and at the same time the rocking shafts are held in such positions as by the
chains to lower the gripping blocks to the lower parts of their guide cheeks. On
the
rope breaking or becoming disconnected the springs act on the rocking shafts
so as to draw up the gripping blocks, and as they move up their guide cheeks they
approach the fixed wooden guides, and gripping them become stationary thereon.
The descent of the cage is not stopped with too great suddenness, but continues
in a gradually retarded manner after the first contact of the gripping blocks on the
fixed wooden guides, forcing the gripping blocks closer and closer in upon the
guides until the momentum of the cage is absorbed and the cage becomes stopped
and securely held. Also, where it can be managed a light safety rope is connected
to a pair of cages or hoists passing up from one cage or hoist over a pulley or pulleys
at the pit head or other top framing and down to the other cage or hoist.
In the case of each cage or hoist the safety rope is connected either directly, or,
as is preferred, through an intervening spring to levers so fixed on the two rocking
shafts as on the safety rope being strained to turn those shafts in the direction for
putting the gripping blocks into action. In ordinary working this light safety
rope is not strained, but on the main rope becoming detached it at once causes the
gripping blocks to act.
The second part of the Invention relates to the prevention of injury from over-
winding, and consists in combining the arrangements herein-before described with
any convenient kind of detaching hooks acted on by stationary stops whenever
the cage is raised at all above its proper height. A slack chain or rope is made to
connect the main rope and the part acted on by the light safety rope, and whenever
the main rope becomes detached the connecting rope or chain becomes tightened,
and causes the gripping blocks to act and prevent the descent of the cage.
The third part of the Invention consists in arranging indicators in connection
with the springs or any moving part of the safety apparatus of mine cages, hoists,
or the like, such indicators consisting of dials with pointers, and being placed in
prominent or easily seen positions on the cage framing, so as to show at all times
the relative positions of the movable parts, and give timely warning if any part
-gets deranged or out of order.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John McKellar Main in the Great Seal Patent Office on the 7th
January 1879.
JOHN MCKELLAR MAIN, of Crossfield Iron Ore Works, in the County of Cumber-
land, Engineer. "IMPROVEMENTS IN SAFETY APPARATUS FOR MINE CAGES, HOISTS,
AND THE LIKE."
My said Invention has for its object to improve the construction and operation of
safety apparatus applied to mine cages, hoists, and the like.
The first part of my Invention relates to the prevention of the descent of the
cage or hoist in the event of the winding or hoisting rope breaking, and my
improved apparatus comprises certain toothed or cross-grooved blocks carried by
the cage or hoist, and arranged so as on the rope breaking to grip the wooden
guides usually fixed at the sides of the pit or other place, and between which the
cage or hoist ascends and descends. There is a pair of the gripping blocks for each
fixed guide, and each block is wedge shaped in side view, the bottom being the
broader end. The outer inclined sides of the blocks are fitted to work on inclined
guides fixed to the framing of the cage or hoist, and the four blocks are suspended
from pulleys or levers on two horizontal rocking shafts carried in the upper part of
the framing. The rocking shafts have levers fixed on their middles, to which levers
there are jointed the lower ends of rods fixed at their upper ends to a cross head,
to which last the winding or hoisting rope is attached.
When the strain due to the weight of the cage acts through the rocking shaft
levers on the rope the levers assume such positions as to lower the gripping blocks
to the lower parts of the inclined guides on the cage. The gripping blocks do not
then touch the fixed vertical guides; but in the event of the rope breaking, springs,
which are applied to the rocking shaft levers, cause the gripping blocks to be
drawn up their inclined guides, and to be thereby closed upon the fixed vertical
guides.
The descent of the cage is not stopped with too great suddenness, but continues
in a gradually retarded manner after the first contact of the gripping blocks on the
fixed wooden guides, forcing the gripping blocks closer and closer in upon the
guides until the momentum of the cage is absorbed and the cage becomes stopped
and securely held. Also, where it can be managed, a slight safety rope is by my
Invention connected to a pair of cages or hoists passing up from one cage or hoist
over a pulley or pulleys at the pit head or other top framing, and down to the
other cage or hoist.
In the case of each cage or hoist the safety rope is connected either directly or
through an intervening spring to levers so fixed on the two rocking shafts as on
the safety rope being over strained to turn those shafts in the direction for putting
the gripping blocks into action. In ordinary working this light safety rope is not
strained, but on the main rope becoming detached it at once insures the action of
the gripping blocks.
The second part of my Invention relates to the prevention of injury from over-
winding, and consists in combining the arrangements herein-before described with
any convenient kind of detaching hooks acted on by stationary stops whenever
the cage is raised at all above its proper height. A slack chain or rope is made to
connect the main rope and the part acted on by the safety rope, and whenever the
main rope becomes detached the connecting rope or chain becomes tightened and
causes the gripping blocks to act and prevent the descent of the cage.
The third part of my Invention consists in arranging indicators in connection
with the springs or any moving part of the safety apparatus of mine cages, hoists,
or the like, such indicators consisting of dials with pointers, and being placed in
prominent or easily seen positions on the cage framing so as to show at all times
the relative positions of the movable parts, and give timely warning if any part gets
deranged or out of order.

page_text: י
And in order that my said Invention and the manner of performing the same
may be properly understood, I hereunto append a Sheet of explanatory Drawings
to be herein-after referred to, and representing my improved safety apparatus as
fitted to a mine cage.
In these Drawings the same reference numerals are used to mark the same or
like parts wherever they are repeated.
Figures 1 and 2 on the accompanying Sheet of Drawings are elevations as at
right angles to each other, showing a mine cage and portions of a pit head framing,
and Figure 3 is a section showing the indicators. At each side of the cage 4, where
it is guided by the fixed vertical wooden guides 5, there are placed two wedge-
shaped gripping blocks 6, which may be made of metal or of metal and wood com-
bined, and which have formed or fixed on their inner vertical faces projecting
points or horizontal knife edges to engage with or bite into the fixed wooden
guide 5 when required. The outer sides of the gripping blocks 6 are inclined, and
are fitted to slide upon guide cheeks 7 fixed to the cage framing. Arms 8 formed
on the backs of the gripping blocks 6 project through slots in the guide cheeks 7,
and are fitted with rollers to run on fixed bars 9 so as to keep the gripping blocks 6
in contact, or nearly so, with the guide cheeks 7, and prevent them from touching
the fixed guide 5 when at the lower and outer parts of the guide cheeks 7. The
gripping blocks 6 are suspended by rods 10 and chains 11 from pulleys 12, which
are fast on two horizontal rocking shafts 13 carried in the upper part of the cage
framing.
Each shaft 13 has a pulley 12 at each end, and the two pulleys at the same ends
of the shafts are connected to one pair of gripping blocks 6, the pulleys at the other
ends being connected to the other pair of blocks. At their middles the rocking
shafts 13 have fixed on them short levers 14, which are jointed to vertical rods 15,
having their upper ends fixed to a cross head 16; and to the middle of this cross
head there is fixed the coupling piece 17 for the attachment of the winding or
hoisting rope 18.
On the rods 15 there are placed a number of rubber disc springs 19, separated by
metal discs, and confined between bottom discs on the rod 15 and the roof plate 20
of the cage, so that the weight of the cage acting on them through the roof plate 20
tends to compress them when the cage hangs on the rope 18. When the springs 19
(for which any other suitable kind may be substituted) are compressed the
rods 15 in passing up through the roof plate 20 move the levers 14, rocking
shafts 13, and pulleys 12 in such a way as to lower the gripping blocks 6 clear of the
fixed guides 5. In the event of the rope 18 breaking or becoming detached the
strain on the springs 19 is removed, and they at once cause the rocking shafts 13
and pulleys 10 to turn so as to move the gripping blocks 6 to the upper and inner
parts of their guide cheeks 7. This makes the blocks 6 to grip the fixed guides 5,
and the tendency of the cage to descend further only increases the tightness of the
grip through the wedging action of the guide cheeks 7 on the backs of the gripping
blocks 6.
Light casings 21 are fixed over the parts at the back of the guide cheeks 7 to
protect them from extraneous matters, and the rods 10 attached to the gripping
blocks 6 are extended up and bended inwards to clear the guides 5, whilst each
pair is in one piece, which is fitted to work on a guide spindle 22 at the top.
On each rocking shaft 13 there is fixed a spur wheel 23, which gears with a
pinion 24 on the arbor of a pointer 25 fitted to work over an indicator dial 26.
The two indicators are placed in the upper part of the cage so as to be easily seen, t
and an inspection of them will at any time show whether the apparatus is in pro-
per working order or not.
.
The apparatus I have herein-before described with reference to Figures 1 and 2
of the Drawings may be used without further additions, but I prefer to combine
with it, when applied to a pair of cages or hoists moving reversely to each other, 5
what I have herein-before referred to as a safety rope. This is a light rope 27,
which is carried from one cage up to and over a pulley 28 at the top, and down on

page_text: the other side to the other cage. The pulley 28 is carried by blocks fitted to
vertical guides 29, and suspended by chains 30 passing over pulleys to weights 31,
which are adjusted to maintain a certain strain on the safety rope 27, whilst
allowing the pulley 28 to fall and rise to accomodate the differences in the sum of
the vertical portions of the main ropes 18 due to the action of the winding drum.
Each end of the safety rope 27 is attached by a pair of short ropes or links 32 to
levers 33 on the rocking shafts 13, such levers 33 being arranged to act reversely
to the other levers 14, or, in other words, when pulled up to cause the blocks 6 to
grip the guides 5. And it follows that, when the main rope 18 of either cage is
detached the consequent pull of the safety rope 27 will at once put the gripping
blocks 6 in action, or assist in doing so.
The coupling piece 17, by means of which the main rope 18 is attached to the
cage, is shown as fitted with a detachable hook 34 formed with a projecting
lever 35, which will encounter a fixed stop whenever the cage is raised above its
proper highest position, and cause the detachment of the rope 18. The cage will
thereupon become fixed by the action of the gripping blocks 6 in the same way as
if the rope 18 had broken.
I connect the upper end of a light rope (or chain) 36 to the main rope 18 at a
point above the connection of the latter to the cage, and the other end of the
rope 36 I connect to the levers 33 on the rocking shafts 13, either through the
ropes 32, or in any other convenient way, so that in the event of the main rope 18
becoming detached at the coupling, the rope 36 will tighten, and put, or assist in
putting the gripping blocks 6 into action.
In cases in which wire guides are used instead of the wooden guides 5 the
blocks 6 have their gripping faces slightly modified to correspond.
Having thus particularly described my said Invention, and the manner of per-
forming the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel and
original, and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent, is,-
1. The arranging or combining together of the parts of safety apparatus for mine
cages, hoists, and the like, substantially in the improved manner herein-before
described.
2. The combination of the pairs of wedge-shaped gripping blocks with the
inclined guide cheeks, and with rocking shafts, which last are fitted with levers
connected to the winding or hoisting rope, and fitted with springs, all being
arranged and acting substantially as herein-before described.
3. The combination of the safety rope (27) with the other parts or with equivalent
parts, substantially in the manner herein-before described.
4. The combination of the detachable hook or equivalent apparatus with the
gripping blocks and parts concerned in their action, for the purpose of preventing
injury from overwinding, and as herein-before described.
In witness whereof, I, the said John McKellar Main, have hereunto set my
hand and seal, this Fourth day of January, in the year of our Lord One
thousand eight hundred and seventy-nine.
JOHN MºKELLAR MAIN. (L.S.)