Improvements in Safety Appliances for Elevators.
Year: 1893

page_text: Complete Specification Left, 7th Jan., 1893-Accepted, 1st Apr., 1893
COMPLETE SPECIFICATION.
Improvements in Safety Appliances for Elevators.
I, RICHARD UREN of Ripley in the County of Houghton, State of Michigan,
United States of America, Gentleman, do hereby solemnly declare the nature of
my invention for IMPROVEMENTS IN SAFETY APPLIANCES FOR ELEVATORS and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The invention relates to safety appliances which are employed in connection
with travelling elevators or lifts to arrest the descent of the car in event the main
hoisting cable breaks or the car otherwise escapes from its control. Instead of
clutches or brakes attached to the car and which are released automatically to act
directly against a rack or rail extending along the way, the present invention
designs to provide a supplemental safety cable with which the car-clamp or grip
can immediately engage when the main-cable breaks or ceases to control the car.
The safety cable is arranged along the path of the grip and by over-head suspen-
sion carries a counter-poise (weight or spring) which comes cumulatively into play
and serves eventually to balance the maximum load) of the run-away car. By such
expedient the descending car is brought ultimately to a standstill but in a gradual
fashion so that sudden shocks are avoided and as well also, the dangers of breakage
at the racks or brake-rails which are apt to occur when the full load and the
impetus of the car are suddenly brought to bear against them.
The exact nature of the improvements will appear from the description following
and be distinctly pointed out by claims at the conclusion thereof.
Referring to the accompanying drawings wherein like parts are distinguished by
like designation throughout.
Fig. 1 is a view in sectional elevation showing the improvements applied to an
ordinary mining car.
Fig. 2 is a detail view of the mining car in side elevation showing the safety
appliance attached.
Fig. 3 is a view of the car in transverse section on line 3-3 of Fig. 2.
Fig. 4 is a view of the car in end elevation.
Fig. 5 is a view (at the side) of an ordinary passenger car and well in section
elevation showing the improvements applied thereto.
Fig. 6 is a detail view of the improved passenger car in front elevation.
Referring to the drawings, Figs. 1-4, the mining car a is of usual structure
mounted upon the wheels b which ride up and down along the rails c of the inclined
way. Conveniently secured for unison movement at opposite sides of the car
body a are the shifting grips d d which (in the form shown) consist of confronting
pairs of segment plates pivotally secured by bolts e to the stout frame fastened
at the back which
to the car body. Each segment plate has a rounded seat
under any severe stress, bears against a corresponding seat formed in the frame,
and thereby relieves the thrust and strain exerted otherwise upon the pivot bolts e.

page_text: These latter allow a
slight play to the segment plates d sufficient to insure the
contact of the seat 9 against the frame when necessary. The confronting edges of
the plates d d are struck upon a curve slightly eccentric with reference to the
pivotal point e, and are preferably furnished with shoes y of copper or like soft
metal, which will tend to embed the cable h when the latter is engaged therewith.
Ordinarily, the companion segment plates d d' which together constitute a grip or
set of jaw clamps are in mesh through the medium of arc-racks i, so as to turn in
unison about the pivot e.
To balance the strain and for orderly play, the grippers are arranged in dual
set, one at each side of the car body, and for safety it is usually desirable to pro-
vide (see Fig. 2) double grips in each separate set. A shifting bar k pivotally
connected with the jaw d'of each grip, is joined at its opposite end to the yielding
connector . As here shown, said connector is branched or bow-like in form and
is pivotally mounted at its forked ends by through bolt m retained in the stout
lugs n which extend from the end of the car body. Heavy tension springs o
fastened to the end of the car and curving outward therefrom rest beneath the
cross rod p which extends between the forks of the yielding connector l. Through
an eye y at the opposite side of the connector is secured the main lifting cable r
which proceeds thence to the winding drum or hoisting sheaves.
From end to end of the pit or well passes the supplemental or safety cable h.
The lower end of said cable is fastened as at s (preferably in permanent fashion)
and ranges along the side of the car body in position between the confronting faces
of the clamp jaw. Guide pulleys t secured at the side of the car serve to maintain
the supplemental cable in proper place between the grip jaws. Ordinarily, the
safety cables will be dual, one at each side of the car, in keeping with the dual
grips which are designed to engage therewith. At the mouth of the pit or over-
head, the safety cable passes over a sheave u there located, and carries at its
extremity a weight which is sufficiently heavy to always maintain the cable h
trim and taut. A series of "pick-up" weights w rest in ledges of the receiver
and are lifted therefrom successively as the balance (or normal) weight rises
under the lifting action of the cable k. All of the weights constitute a counter-
poise cumulative in character and which increases in amount, according as the
balance rises higher and higher in the receiver. In lieu of the weights it is plain
that a series of springs of increasing power could be arranged in like fashion and
be brought successively into play to accomplish the same cumulative effect.
"
In usual operation the main cable sustains the car a through the medium of
the yielding connector which latter turns slightly about its pivot bolt m against
the tension resistance of the spring o. When thus turned, the connector through
the shifting bark operates the grip jaws d d and distends the same sufficiently to
permit the jaws to play freely past the safety cable . Should the main cable
break or the car otherwise be no longer within its control, the pulling strain of the
main cable upon the yielding connector is relaxed, which latter thereupon yields
slightly about its pivot under action of the springs o, and compels the shifting
bark to actuate the grip jaws d d'. The movement of the grip jaws towards each
other causes them to tightly clamp the supplemental cable and thus transfer the
car suspension from the main cable to the safety cable h and its counter-poise
resistance. As the car descends, the amount of weight added at the counter-poise
gradually increases until finally it is sufficient to completely balance or over-
balance the load and thus ultimately to arrest or materially lessen the flight of the
The normal weight is generally made sufficient to serve a counter-poise for
the empty car; the additional weights which develope the cumulative effect are
provided in total amount necessary to exceed the maximum load to be carried by
the car.
car.
passenger
A convenient plan for applying the invention to the ordinary style of
lift, or elevator car used in buildings, is shown by Figs. 5 and 6. The car of
usual structure moving in the well between the ordinary guide rails, is furnished
with the familiar transom y. An eye-bar extends freely through the transom y

page_text: and is furnished with a headed end 1 which rests normally against the under face of
the transom whilst the car is in operation.
Instead of being pivoted, the yielding connector l'here shown, has a rectilineal
play, and is carried as at 2, by a boss formed upon the eye-bar . The connector /
bas a hub-like centre through which the eye-bar z plays, and at the outer
terminals of its arms the connector is pivotally joined to the shifting bars which
are united in turn to the clamp plates D D' of the grips. The grips are pivotally
mounted as at E upon the car, and are preferably furnished with confronting
copper blocks and with toothed sectors as already detailed. The safety cables h
extend between the jaws of the dual grips at opposite sides of the car and pass
around the over-head sheaves u to the counter-poise receiver and the set of
cumulative weights vw.
In ordinary operation the main cable lifts the eye-bar z so that the headed end
thereof contacts with the transom y and thus serves to suspend the car.
Under the
lifting action of the main cable r, the boss upon the eye-bar slightly raises the
connector against the resistance of the coiled springs 3, which latter remain under
tension so long as the cable r is in normal play. When the yielding connector
is thus lifted, it actuates the shifting barsk k¹ and thus distends the jaws of the
grips so that the latter are free from clamp contact with the supplemental cable h.
The limited play at the eye har z not only sets the grip jaws apart in readiness to
act under stress of the tension-springs 3, but also brings the head 1 of the eye bar
against the under face of the transom y so that the load is primarily carried
thereby, and undue stress upon the springs 3 wholly avoided. The tension of said
springs, however, is always in play and when the main cable r breaks or for any
reason ceases to control the travelling car and its load, the springs 3 are retracted
thereby clamping the grips D D₁ against the safety cables h, and necessarily
effecting the suspension of the car from said supplemental cables, and bringing the
cumulative counter-poise w into play as an over-balance.
From the foregoing description it is manifest that the improvements are not
limited to the mere details of structure set forth, since these may be varied
according to the skill of the mechanic, without departing from the spirit of the
invention, the main purpose of which is to provide a supplemental or safety cable
with a cumulative counter-poise connected therewith and which cable comes auto-
matically into play by grip attachment with the car at such times only when the
car has been lost from the control of the main hoisting cable.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In elevators, the combination with the travelling car and with its main
cable, of the yielding connector between them, the shifting grip controlled thereby,
the supplemental or safety cable located along the path of said grip and the
counter-poise attached to said safety cable, substantially as described.
2. In elevators, the combination with the travelling car, and with its main cable,
of the intermediate yielding connector attached respectively thereto, the gripper
mounted upon said car, the shifting bar between said connector and gripper to
actuate the latter, the supplemental or safety cable located along the path of said
gripper and the cumulative counter-poise attached at one end of said safety cable,
substantially as described.
3. In elevators, the combination with the travelling car and with its main cable,
of the yielding connector between them, the dual grippers mounted upon opposite
sides of said car, the shifting bars therefor located at opposite car-sides and
joining said grippers respectively with the yielding connector, the dual safety
cables arranged along the paths of the respective grippers and the cumulative
counter-poise attached at one end of each of said safety cables, substantially as
described.
4. In elevators, the combination with the travelling car with its main cable, of

page_text: the yielding spring connector between them, the confronting and intermeshing
clamp plates or grip jaws pivoted to the car, the shifting bar joined respectively to
said grip and connector, the safety-cable located along the path of the grip and
between the jaws thereof and the cumulative counter-poise attached at one end of
said safety cable, substantially as described.
Dated this 6th day of January 1893.
J. E. EVANS-JACKSON & Co.,
Agents for the Applicant.