Improvements in Safety Appliances for Lifts, Hoists, and the like.
Year: 1891

page_text: Date of Application, 8th Oct., 1891
Complete Specification Left, 8th July, 1892-Accepted, 13th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Safety Appliances for Lifts, Hoists, and the like.
I, ROBERT MIDDLETON, of Sheepscar Foundry, Leeds, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
It has reference (1) to automatically setting in action gripping devices such as
are capable of safely holding a cage when a main rope breaks, and too great a
speed is attained by a cage in its descent; (2) to an improved mode of securing
the ends of guide ropes and other such supports, so that when suddenly gripped a
falling cage may be brought to rest more gradually; and (3) to an improved
arrangement of the details of my safety wedges, described in my Patent No. 15,292
of 1887, and their neighbouring parts.
The invention has for its object the greater security of cages by making the
safety appliances act with greater promptitude and more certainty; and for
providing means for avoiding the sudden jerks which are thrown on the guiding or
other supports when the safety clutches grasp them.
The gear used by me for releasing the gripping catches is in a manner similar
to that described in my Patent No. 2,109, of 1889, except that when the governor
(which may have as many centrifugal weights or hammers as may be found
desirable for releasing the adjacent tappet lever, which may be arranged and held
in place in several ways) runs at too great a speed an additional gripping device
is released and caused to grasp the safety rope, which thus more promptly and
surely pulls the gripping wedges of the cage into contact with the guides.
When there are no gripping wedges on the cage then the first mentioned
gripping device is made to grasp the additional safety rope which must then be of
such a strength as will support the cage.
In cases where the arrangement of the ropes and their strengths permit it, the
first mentioned gripping device or devices are made to grasp any rope or ropes then
passing through their jaws, and thus hold up the cage.
When guides are grasped, any undue jerk can be met with an arrangement of
volute springs, or by the appliance described in the next paragraph.
In this arrangement instead of securing a rope directly to its support, I attach it
to, and wrap it round, a drum mounted on an axis attached to the overhead gear,
This drum is so nipped by a screw brake or brakes that it easily bears the ordinary
weight put upon it without turning; and yet when the drum is dragged round by
the unusual strain it is so geared that it increases the nip already given and so brings
all gradually to a standstill.
The improved details of my safety wedges consist partly in combining therewith
certain adjustable guide blocks, which keep the cage in line and prevent the
wedges from shaking into gear, and partly in the general arrangement of the parts
with a special view of allowing greater accuracy to be obtained in fitting up the
cages and adjusting them to the guides.
In cases where as in the ordinary coal-pit-two cages are used, with a strong
safety rope to enable one to balance the other as far as possible, one or more of
my centrifugal governors with their weights or hammers are capable of being
arranged to so strike the tappet lever-in whichever direction they are running-as
to release the additional gripping devices and in that manner grasp, both on the up
and down side, each rope passing through them; that is to say, both the safety
ropes and any other ropes around which the gripping apparatus may be arranged.

page_text: COMPLETE SPECIFICATION.
Improvements in Safety Appliances for Lifts, Hoists, and the like.
I, ROBERT MIDDLETON, of Sheepscar Foundry, Leeds, in the County of York,
Engineer, 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 :-
It has reference (1) to automatically setting in action gripping devices such as
are capable of safely holding a cage when a main rope or gearing breaks, and too
great a speed is attained by a cage in its descent; (2) to an improved mode of
securing the ends of guide ropes and other such supports, so that when suddenly
gripped a falling cage may be brought to rest more gradually; and (3) to an
improved arrangement of the details of my safety wedges, described in my Patent
No. 15,292 of 1887, and their neighbouring parts.
The invention has for its object the greater security of cages by making the
safety appliances act with greater promptitude and more certainty; and for
providing means for avoiding the sudden jerks which are thrown on the guiding
or other supports when the safety clutches grasp them.
In order to fully describe my invention I have annexed two sheets of drawings,
on which
Fig. 1 is a plan and Fig. 2 is a side elevation of my automatic rope-gripper.
Figs. 3 & 4 are elevations of two strain-relieving appliances for fitting to guide
and lifting ropes.
Fig. 5 is a diagrammatic front elevation of a multiple rope-gripping appliance
for balanced cages.
Fig. 6 is side elevation of the tripping lever and two side levers of the same,
and Fig. 7 a corresponding plan of these latter.
Figs. 8 & 11 are front elevations, Figs. 9 & 12 are side elevations, and
Figs. 10, 13, & 14 are plans of my improved combined arrangement of guides and
safety wedges.
The gear used by me for releasing (i.e. bringing into action) the gripping-catches
is in a manner similar to that described in my Patent No. 2,109 of 1889 except
that when the governor (which may have as many centrifugal weights or hammers
as may be found desirable for releasing the adjacent tappat lever, which latter
may be arranged and held in place in several ways) runs at too great a speed an
additional gripping device is released and caused to grasp the safety rope, which
thus more promptly and surely pulls the gripping wedges of the cage into contact
with the guides.
.In Figs. 1 & 2 A is the safety rope, which in running round the pulley B,
actuates the governor C, here shown with two hammers C¹, C. When an excessive
speed is attained the tappet lever D is struck, and the weighted lever E is released.
This causes the wedging-jaw F to descend also, and close on the rope A, holding it
securely against the fixed jaw G. A small copper pin H is used for holding the
lever E up (ont of gear) in this case. The general arrangement of the appliance
on one common base is clearly shown. The complement of hammers should balance
one another. The two cheeks of the hammers span the governor wheel, through
which the suspending bolt passes-the spring etc. being also clearly shown on the
drawings.
When there are no gripping wedges on the cage then the first mentioned
gripping device (wedging-jaw) is made to grasp the safety rope which must then
be of such a strength as will support the cage.
In cases where the arrangement of the ropes and their strengths permit it the
first mentioned gripping device or devices (wedging-jaw) may be made to grasp
any rope or ropes then passing through their jaws, and thus hold up the cage.
When rope, or other like, guides, are grasped, any undue jerk can be met with

page_text: an arrangement of volute springs, or by the appliance described in the next
paragraph.
In this arrangement shown in Fig. 3-instead of securing a rope J directly to
its support, I attach it to, and wrap it round, a drum K mounted on an axis L
attached to the overhead gear. This drum is so nipped by a screw brake or brakes
that it easily bears the ordinary weight put upon it without turning; and yet when
the drum is dragged round by the unusual strain it is so geared that it increases
the nip already given, and thus brings all gradually to a standstill. Here the
pinion L', driven by the drum K, drives the wheel M the boss of which, turning
on a suitable screwed and fixed bolt or shaft N, further tightens the two sides
frames O. O, against the ends of the drum. Between the frame sides and the
drum ends semi-yielding pieces P, P, may be introduced as shown. An adjusting
bolt is also provided for regulating the strain. If the appliance is affixed to a
cage and the rope led suitably upwards, it will be applicable to. cases where the
only safety appliance is the wedging-jaw working in connection with a strong
safety-rope capable of taking the weight of the whole cage-when called upon.
Another such strain-relieving appliance (suitable for fixing to a cage) is shown
in Fig. 4, where A is the rope, and K the drum, which whilst uncoiling moves
forward, on the screwed and fixed shaft N, against a powerful volute spring or
other yielding body. R, which gradually brings it to a stand. The shaft N is
suitably supported at each end by the framing O, O', and in order to hold the
drum in its working position, a pawl and ratchet wheel, as at S, is provided.
This appliance could of course be arranged to support a guide rope in cases where
such ropes or rods are to be grasped suddenly. The endwise movement of the
drum on the shaft, and that due to the gradual uncoiling of the rope, should be
made to oppose one another, so that the point of suspension of the cage may.
remain as stationary as possible.
The improved details of my safety wedges consist partly in combining therewith
certain adjustable guide blocks, which keep the cage in line and prevent the wedges
from shaking into gear, and partly in the general arrangement of the parts with a
special view of allowing greater accuracy to be obtained in fitting up the cages and
adjusting them to the guides. Figs. 8, 9 & 10 show my arrangement of adjustable
guide blocks, a pair T, and T', for grasping the guide bars, rods, or ropes U,
being mounted on a common base V. These guide blocks, one of which, T',
encircles the safety rope or rod A' on its way to the safety wedge W below, are
fixed at the head of the cage one on each side. Figs. 11, 12, 13 & 14 show the
arrangement of guide blocks T², T', and safety wedge W, which are mounted on a
common base V and are fitted, one on each side, at the foot of the cage. The
safety wedge has a dove-tailed groove W' cut in its slanting side, into which is
fitted a special head of the bolt X, fixed as shown. By this means the wedge is
held steadily in position so that it cannot engage with the guide until drawn up
by the safety rope A. When drawn up the wedge engages directly any descent
commences. Adjusting screws are shown at t, t, etc.
In cases where as in the ordinary coal pit-two cages are used, with a strong
safety rope, in addition to the ordinary one, to enable one to balance the other as
far as possible, one or more of my centrifugal governors with their weights or
hammers are capable of being arranged to so strike the tappet lever-in whichever.
direction they are running-as to release the additional gripping devices, and in
that manner grasp, both on the up and down side, each rope passing through them;
that is to say, both the safety ropes and any other ropes around which the gripping
apparatus may be arranged.
In Fig. 5 the pulley B carries the additional safety rope A, and on its shaft my
governor, C, with its hammers, C' to C4, arranged to operate on the head of the tappet-
ever D, regardless of the direction of revolution. The lever D has a fulcrum at D',
and at its foot has two pins D' standing out on each side as shown. Two weighted
evers El & Eare connected with the wedging-jaws at F1 and F which surround the
up and down ropes as shown. The ends of these levers, furthest from their fixed fulcra,

page_text: are bent at right angles so that they may rest on the pins D' as shown in Figs. 6
and 7. With this arrangement it follows that whichever way the tappet-lever D
is moved the levers E & E' will be released, and will allow the wedging jaws to
come into action. The ascending rope will not of course be fully grasped by the
wedge until it has come to a stand. By arranging the required number of lower -5
levers, such as D³, any number of wedging-jaws may be released so as to seize as
many guide ropes, & the like, as may be desired. Where a safety rope is used as
a balancing rope an abrupt action of the wedging-jaws is not to be desired, hence
smooth faces etc., may be arranged to bring about gradual stoppages..
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
(1) The automatic rope-gripper arranged, constructed, and operated substan-
tially as described and shown-with special reference to Figs. 1 & 2 and 5, 6 & 7—
with the object and for the purpose set forth.
(2) The apparatus for relieving a gripped rope from sudden strains, arranged,
constructed and operated substantially as described and shown-with special
reference to Figs. 3 and 4-with the object and for the purpose set forth.
(3) The general arrangement of guide-blocks and safety-wedge, substantially
as described and shown in Figs. 8 to 14 with the object and for the purpose set
forth.
(4) The combination of the automatic rope-gripper, and the strain-relieving
apparatus substantially as and for the purpose set forth.
(5) The combination of the automatic rope-gripper and the safety wedges fitted
to a cage, with or without the strain-relieving appliance attached to the guide rods,
substantially as and for the purpose set forth.
Dated this 7th day of I„l» 1809
1
1
WM.
SNOWDON,
9, Old Bank Chambers, Leeds, Yorks, Agent for the Applicant.