IMPROVEMENTS IN SAFETY CAGES OR APPARATUS FOR MINES."
Year: 1857

page_text: LETTERS PATENT to Robert Aytoun, of Edinburgh, in the County of
Mid Lothian, North Britain, Writer to the Signet, for the Invention of
"IMPROVEMENTS IN SAFETY CAGES OR APPARATUS FOR MINES."
PROVISIONAL SPECIFICATION left by the said Robert Aytoun at the
Office of the Commissioners of Patents, with his Petition, on the 27th
August 1857.
I, ROBERT AYTOUN, of Edinburgh, in the County of Mid Lothian, North
Britain, Writer to the Signet, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN SAFETY CAGES OR APPARATUS FOR MINES," to be as
follows, that is to say:-
This Invention relates to the arrangement and fitting up of mine cages or
the lifting and lowering apparatus employed in working mine shafts, in such
manner as to obtain security from accidents in cases of fracture of the winding
rope or suspensory apparatus. In cages fitted up in this way, four strong
blade springs are provided for each cage, two for each guide in the shaft.
These springs are so contrived that they have a constant tendency to grasp or
clip the guides, and have a strong frictional hold upon them. The lower
portions of these springs are firmly attached to the cage body, whilst their
upper ends are jointed by means of suitable links to a set of levers carried

page_text: by the cage top; the inner contiguous ends of these levers are jointed to fixed
centres upon the cage, whilst their outer free ends are connected to the actual
winding rope. The result of this arrangement is that so long as the winding
rope is in order, its tensional actual keeps the clipping springs free from
contact with the guides, but on the failure of the rope and the consequent
tendency of the cage to fall down the shaft, the springs clip the guides and
hold the cage firmly up.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Aytoun in the Great Seal Patent Office on the
27th February 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
AYTOUN, of Edinburgh, in the County of Mid Lothian, North Britain, Writer
to the Signet, send greeting.
WHEREAS Her most Excellent, Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of August in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Robert Aytoun, Her special license that I, the said Robert Aytoun,
my executors, administrators, and assigns, or such others as I, the said
Robert Aytoun, my executors, administrators, or assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
SAFETY CAGES OR APPARATUS FOR MINES," upon the condition (amongst others)
that I, the said Robert Aytoun, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
·Patent.
NOW KNOW YE, that I, the said Robert Aytoun, 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 in writing, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-

page_text: My said Invention relates to the arrangement and fitting up of mine cages
or the lifting and lowering apparatus employed in working mine shafts, in
such manner as to obtain security from accidents in cases of fracture of the
winding rope or suspensory apparatus. In cages fitted up in this way, four
strong blade springs are provided for each cage, two for each guide in the
shaft. These springs are so contrived that they have a constant tendency to
grasp or clip the guides, and have a strong frictional hold upon them. The
lower portions of these springs are firmly attached to the cage body, whilst
their upper ends are jointed by means of suitable links to a set of levers
carried by the cage top; the inner contiguous ends of these levers are jointed
to fixed centres upon the cage, whilst their outer free ends are connected to
the actual winding rope. The result of this arrangement is that so long as
the winding rope is in order, its tensional action keeps the clipping springs
free from contact with the guides, but on the failure of the rope and the
consequent tendency of the cage to fall down the shaft the springs clip the
guides and hold the cage firmly up.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the several illustrative figures on the explanatory Sheet
of Drawings which I have hereunto appended, for the purpose of showing
certain modifications under which my improvements may be judiciously.
carried out in practice.
Figure 1, on my illustrative Drawing, is a front view of one modification of
my improved safety cage; Figure 2 is a side elevation corresponding to
Figure 1. The wooden framing A, built at the mouth of the shaft B, and
partially overhanging the same, is of the kind in ordinary use.
Each pair
of the guides C serves to direct the ascent and descent of the cage D fitted
thereto. The construction of the double cages does not differ from those in
general use, the safety apparatus for checking the descent of the cage in the
event of the rope or chain breaking or otherwise failing being an appliance
fitted thereto. To one of the horizontal stay pieces E, on each side of the
framing of the cage D, is secured a pair of brackets or "buckles," to each of
which is bolted a strong compound blade spring F; the blade spring F are
curved inwards, so that their upper ends rest and press with great force
against the sides of the guides C. The pressing surfaces of the spring F,
where they come in contact with the guides, are roughened or made with
coarse rasp-like teeth, somewhat similar to the talons of a cat, for the
purpose of taking a firmer hold. A short link G is attached to the upper end
of each of the springs F, the other end of which is secured by a bolt or other
attachment to the short arm of a bell crank lever H. Each of these bell

page_text: erank levers is centred upon a stud, carried by the upper cross rail of the
frame. The longer arm of each of the bell crank levers H is linked to the
end of a chain I, the four arms of the levers H being connected by the chains
I, which are made fast to a shackle J. The shackle is hung upon and
suspended by the hook K; this hook is attached by a shackle L to the short
chain M, forming the extremity of the ordinary winding rope N. The hook K
is so arranged as to release the cage when wound up to a certain height, and
thereby prevent over winding. For this purpose the upper part of the hook is
prolonged outwards, and forms a catch, which strikes against the stop O
on the under side of the overhanging part of the framing A. The hook K is
kept down in its place in the eye of the shackle J by the pressure of a spring
P acting upon the back of the hook. In the event of the cage being wound
beyond its proper height, the projecting part of the hook K comes in contact
with the stop O; the impact of the blow overcomes the pressure of the
spring P, the hook K is released from the shackle J, and the cage is arrested
in its descent by the pressure of the springs F against the sides of the guides.
The cage D being suspended by the chains I attached to the bell crank
levers H, its weight causes these levers to turn partially upon their axes; this
motion draws the links G outwards, and thus prevents the springs F from
coming in contact with the sides of the guides C. When, however, an accident
occurs to the rope, or the cage is disengaged from it by the operation of the
before-mentioned catch, the chains I are released, and the springs instantly
grasp the sides of the guides with sufficient force to arrest the descent of the
cage at once.
The tenacity with which the springs grip the guides C is
greatly increased by the sharp, claw-like projections on their under sides.
When the cage is wound up to the pit's mouth, the rope is slackened, when
the cage rests upon the platform; the springs then come in contact with the
guides. To prevent these from being injured, they are faced on each side
with a piece of hard wood, which may readily be renewed. from time to time;
a like precaution is used to preserve the guides at the bottom of the shaft.
To prevent the whole weight of the cage from being thrown on to the springs
F, the levers H may be arranged to come in contact with the stops Q, which
are fitted on to the upper rail of the cage or form a part thereof. Single
blade springs may be used in lieu of the springs F, or volute springs may be
adapted for the purpose, in which case an arrangement of eight of these
springs will be found more convenient in practice. With this arrangement
of safety apparatus for mines, accidents arising from the breaking of the rope
or from over winding are rendered harmless, and loss of life and property from
this cause thereby prevented.

page_text: Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of safety cages or appa-
ratus for preventing accidents arising from over winding or the breakage of
the rope used for lowering and raising the cage, as herein-before described.
Second, the system or mode of stopping the descent of mining cages by
means of springs, which are caused to grasp the sides of guides upon the
breakage or failure of the winding rope, as herein-before described.
Third, the system or mode of bringing the springs into action upon the
winding rope being severed or otherwise detached from the cage, as herein-
before described.
In witness whereof, I, the said Robert Aytoun, have hereunto set my
band and seal, this Twenty-fifth day of February, One thousand eight
hundred and fifty-eight.
ROBERT AYTUUN. (L.S.)