ELECTRICAL SAFETY APPARATUS FOR LIFT CAGES
Year: 1884

page_text: I, NOAH COWARD of Gunnislake near Tavistock in the county of Devon, Mine
Agent, do hereby declare the nature of my said invention for "ELECTRICAL SAFETY
APPARATUS FOR LIFT CAGES" to be as follows:-
My invention relates to apparatus for effecting by means of electricity the
stoppage of the cage of a lift in case of the breaking of the rope or chain by
which it is raised, or in case of overwinding.
For this purpose, I apply to the cage pivotted brake arms which as long as they
retain a certain attitude are free, but which act as brakes when they becomo
canted. The arms are held in the free attitude by a trigger worked by the
armature of an electromagnet as long as a current of electricity is maintained
through the coil of the magnet. This electricity is conducted by insulated wires
passing from a battery along or within the hauling rope or chain. When the rope
or chain breaks, the electric conductors are at the same time severed, and the
magnet then ceasing to attract its armature, the trigger is released and the arms of
the cage become canted so that they act as brakes stopping movement of the cage.
The rope or chain is connected to the cage through a clamp which, in case of over-
winding, is opened apart by encountering a wedge piece fixed at the top of the
lift, and thus the cage is freed from the rope or chain, and, the electrical conductor
being at the same time severed, the cage is stopped as above described.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: I, NOAH COWARD of Gunnislake, near Tavistock in the county of Devon, Mine
Agent do hereby declare the nature of my invention for "ELECTRICAL SAFETY
APPARATUS FOR LIFT CAGES," and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:-
My invention relates to apparatus for effecting by means of electricity the
stoppage of the cage of a lift in case of the breaking of the rope or chain by
which it is raised or in case of overwinding. For this purpose, I apply to the cage
pivotted brake arms which as long as they retain a certain attitude are free, but
which act as brakes when they become canted. The arms are held in the free
attitude by a trigger worked by the armature of an electromagnet as long as a
current of electricity is maintained through the coil of the magnet.
This electricity is conducted by insulated wires passing from a battery along or
within the hauling rope or chain. When the rope or chain breaks the electric
conductors are at the same time severed, and the magnet then ceasing to attract
its armature, the trigger is released and the arms of the cage become canted so that
they act as brakes stopping. movement of the cage. The rope or chain is connected
to the cage through a clamp which, in case of overwinding, is opened apart by
encountering a wedge piece fixed at the top of the lift and thus the cage is freed
from the rope or chain and the electrical conductor being at the same time severed
the cage is stopped as above described. Fig. 1 of the accompanying drawings
shews a side view of a cage or skip provided with safety appliances constructed
according to my invention, the said apparatus being shewn in the position which
occupies when the cage is at work. Fig. 2 shews the same view with the brake
apparatus put in action when the hauling rope or chain is broken; fig. 3 shews
a back view of the cage shewing the handle formed as a clamp for holding the
hauling rope or chain, a side view of this in the position in which it holds the rope
being shewn at fig 1 while a side view of the same in the opened position is shewn
at fig..5. Fig. 4 shews a plan of the same in the closed position; fig. 6 shews
a plan of the winding drum with the arrangement for conveying the electrical
current from a battery to the insulating conducting wires in the hauling rope.
Figs 7, 8 and 9 shew respectively a side elevation, a plan and a sectional plan of
the electrical trigger gear for holding the brake apparatus in the position shewn at
fig. 1 and for releasing it as at fig. 2 when the hauling rope breaks. The cage
or skip A is provided on each side with two levers B B fixed on shafts CC that
are carried in bearings-fixed to the cage. The free ends of the levers are pivotted
to rods D D that are fixed to plates or skids E E situated on opposite sides of the
vertical guide beams FF; the skids E are made to extend from the upper levers to
the lower ones, so that the levers together with their rods and skids form a parallel
motion that can assume either the position shewn in fig. 1 or that shewn in fig. 2.
When the levers are in the position shewn in fig. 1, the skids are sufficiently far
removed from the guide beams to allow of their passing freely up and down along
the same with the cage and when this is in working order the levers and skids are
held in this position by an electrical catch or trigger arrangement to be presently
described,

page_text: On the breaking of the hauling rope G, the catch is released, whereupon the
weight of the cage bearing upon the ends of the levers pivotted thereto in
combination with the action of the springs T to be presently described, causes
them to assume the inclined position shewn at fig. 2 in which the skids are made
to nip the beams F firmly between them, whereby the cage is held securely against
falling. For this purpose, the hauling rope G contains within it two insulated
conducting wires H through which an electrical current is passed from a battery
above to the coils of an electromagnet I fixed in a closed box J at the bottom of
the skip or cage. In the arrangement shewn in the drawing a compartment A³
is formed below the usual inclined bottom A¹ of the skip by extending the sides
downwards, for the reception of the box J and a space A³ is left between the
bottom of the compartment and the box in order to preserve the latter from violent
concussion, should the skip accidentally fall through a considerable height. The
armature K of the electro-magnet is pivotted to the casing at K' and is connected
by a link L to a double ended lever M pivotted to the casing at M¹ and urged by
a strong springs N into the position indicated by the dotted line. The free end of
the lever takes into the slot of a bar O having a notch at O¹ into which takes the
end of a lever P, pivotted to the top of the box. The upper end of this lever is
formed as a catch P₁ which holds the end of an arm Q on a shaft Q' carried
in bearings on the top of the box, and having fixed on its ends two side levers R R
connected by a cross bar R'. This cross bar is connected by a rod S to one of the
transverse rods D of the levers B and also by springs T to the cage A,' which
springs raise the levers R into the dotted position.
From the above described arrangement it will be seen that when the electro-
magnet I is rendered active by the passing of an electric current through the
hauling rope, the armature maintains the lever M and consequently the catch P¹ in
the position shewn at figs 1 and 7 in which the latter engages with the arm Q
so that the levers R are caused by means of the rod S to hold the levers B in the
position shewn at fig. 1, in which, as before stated the skids E can move freely up
and down along the guide beams F. On the fracture of the hauling rope however
the electric current being intercepted and the electromagnet becoming inoperative,
the armature K releases the lever M, which being urged by the springs in its turn
causes the arms Q to be released from the catch P. The levers R being now' free
to follow the upward impulse of the springs T, they push up the free ends of the
levers B by means of the rod S while at the same time the weight of the cage
tends to depress the pivotted ends thereof and thus the levers are brought into the
before described inclined position shewn at fig. 2 in which the skids are made to
nip the beams F tightly between them and thus to prevent the downward motion
of the cage.
The spindle of the catch P¹ is provided with a spill P' on which may be fitted a
hand lever P for the purpose of bringing the parts O M and K back into their
original position when the apparatus is to be put in action again. The current
from any available source of electricity may be conveniently conveyed to the
conductor in the hauling rope by the arrangement shewn in fig. 6, in which the
wires from the battery or other source of electricity are connected by pinching
screws to two contact springs, in contact with two insulated metal rings cc on the
winding drum shaft d, the inner ends of the two conductors of the hauling rope
are passed through a boring of the shaft and are put in contact with the rings c.
The conducting wires H pass from the lower end of the hauling rope down at
the back of the cage and enter the box J through a stuffing box U and are connected
to the coil of the electromagnet; a stoppered opening is provided at V in the box
to gain access to the electromagnet and other parts of the apparatus.
For releasing the cage when overwinding of the rope takes place, the handle or
loop W of the cage is constructed of two separate hinged parts as shewn which
when fitted together clamp between them a conical ferrule Gi fitted upon a swelled
part of the rope G, the handle being secured in the closed position by catches XX
pivotted to the one part of the handle and situated in slots formed in both parts so̟

page_text: that when these are fitted together the catches take on to the sides of the notches
on the other part and thus hold both parts together as shewn at fig: 4.
I
The parts of the handle are slightly notched out on the inner side of the catches
as shewn at fig. 4, so that when the cage has been raised to the position shewn at
figs. 1 and 3 the points of two wedges Y enter the notches of the clamp and on
the continued upward motion of the cage the wedges push the catches X away
from the sides of the slots and at the same time push the two parts of the clamp
asunder so as to release the hold thereof upon the rope.
The cage will now drop slightly until by the fracture of the weak conducting
wires H the electromagnet ceases to act whereupon the brake levers B and skids E
will come into action as before described; and thus prevent the further descent of
the cage.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that what I claim is
1, The use of safety appliances to lift cages wherein an clectrical conductor
combined with the hauling rope or chain conveys an electrical current to an electro-
magnet in the cage the armature of which controls the action of brake levers
in the cage in such manner that on the breaking of the rope and consequently of
the conductor the said brake levers are brought into action so as to stop the
descent of the cage, substantially as herein described.
2, The use in combination with the safety apparatus referred to in the preceding
claim of a clamp on the cage so arranged that in case of overwinding, the clamp is
acted upon by wedges so as to open out and release the hauling rope or chain
whereby the electrical conductor combined therewith is severed and the said safety
apparatus brought into action, substantially as herein described.
.
T
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.