Automatic Locking Arrangement for Controlling Gear on Hydraulic or other Lifts.
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
Automatic Locking Arrangement for Controlling Gear on
Hydraulic or other Lifts.
I, ROBERT MACK, of 43, Morrison Street, Lavender Hill, London, SW.,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention has for its object to prevent the unauthorized operation of the
handing rope, chain. or rod, whereby the valve or other controlling gear of a
hydraulic or other power operated lift is actuated, and the invention consists of an
automatic locking device for the said controlling gear capable of being released
only from within the cage so that the setting in motion of the cage by accident or
design is effectually prevented
This locking device consists essentially of a pair of gripping jaws (whereof
one or both may be movable) the jaws being adapted to grip the handing rope,
chain, or rod, through the action of lever, wedge, cam, or toggle mechanism,
in such manner as to prevent the said rope, chain, or rod, being moved in either
direction.
One arrangement consists of a pair of wedge-like jaws working in opposite
directions within a box or casing by which they are so guided as to cause them to
approach and recede from the rope, chain, or rod, passing between them, the said
jaws being operated by a lever to which they are coupled at opposite sides of its
fulcrum, the said lever being actuated in the one direction by a spring or weight
and in the other by the foot or hand of the lift attendant, the locking device
heing mounted in any convenient position in or upon the cage and operated only
from within the cage.
It will be obvious that only one jaw may be movable and the other be fixed and
that, instead of the wedge motion, cams or toggle gear may be used and operated
in a similar manner.
A. M. & WM CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
COMI DIC
Automatic Locking Arrangement for Controlling Gear on
Hydraulic or other Lifts.
I, ROBERT MACK, of 43, Morrison Street, Lavender Hill, London, S.W.,
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:-
My invention has for its object to prevent the unauthorized operation of the
handing rope, chain, or rod, whereby the valve or other controlling gear of a
hydraulic or other power operated lift is actuated, and the invention consists of an
automatic locking device for the handing rope, chain, or 10d, capable of being
released only from within the cage so that the setting in motion of the cage
ID 621

page_text: by any person acting on the handing rope, cham, or rod, from without the cage,
whether by accident or design, is effectually prevented.
The locking device consists essentially of a pair of gripping jaws (whereof
one or both may be movable) mounted upon the lift cage, and caused to grip
the handing rope, chain, or rod, by spring-actuated lever, wedge, cam, or toggle
mechanism, in such manner as to prevent the said rope, chain, or 10d, being
moved in either direction for operating the valve or controlling gear, the release of
the gripping mechanism being effected by a pedal o handle so arranged as to be
operated only from within the cage.
The invention is illustrated in the arcompanying drawings, forming part of
this Specification, wherein
Figure is a part sectional side elevation, and Figure 2 a plan (partly in
section on line 2-2 Figure 1,) of one form of the locking device.
Figure is a part sectional side elevation of one modification
Figure is a part sectional side elevation, and Figure 5 a sectional plan of a
second modification.
Figure 6 is a part sectional side elevation of a third modification, and Figure 7
is a sectional side elevation shewing the adaptation of the locking device shewn in
Figure 1 to act on a chain instead of a rope.
The arrangement generally preferred is illustrated in Figures and 2, and
comprises a pair of wedge-like gripping jaws A, A', working in parallel guides ¿, el,
oppositely inclined to the axis of the handing rope B to correspond to the wedge-
like form of the jaws, said guides being formed within a box or casing C
attached to the underside of the floor D of the lift cage. The gripping
jaws A, A, are similar in every respect, but are placed within the box Cin
positions inverted relatively to one another, SO that their inner or gupping
faces a, a, are parallel to the axis of the handing rope, chain, or 10d, B, the
gripping faces being hollowed SO as partly encircle the rope, chain, or rod
The gripping jaws A, A', 1cceive simultaneous motion in opposite directions
along their guides e, d, from a1 lever formed of two members E, E, acting
together as one and fulerumed on studs E. E¹, having a common axis midway
between the gripping faces of the jaws A, A. said studs being fixed preferably
to the sides of the box or casing C The members E are connected on one
side of the axis to the Jaw A and on the other side to the jaw A¹, the
connection being made by pins or bolts F, F, passing through slots in the
sides of the box C to allow of angular movement of the pins F, F, about
the lever axis, the pins F. F¹, engaging with horizontal slots in the back of
the gripping jaws A. A', to permit of the movements of the jaws towards
and away from each other, consequent on the inclination of the guides c. c.
The members E, E, are prolonged in one direction to form a lever of sufficient
length and are compled to a pedal rod G passing up through the floor of the
cage The lever is normally pressed upwards by means of a spring
as to cause the gripping faces a, a, of the jaws A. A. to approach and grip between
them the handing rope, or its equivalent B When thus gripped the rope cannot
be pulled either up or down from without the cage since, owing to the opposite
obliquity of the two jaws, a pull which tends to release the one jaw tends to
tighten the other, but the strength of the spring or springs H. may be so adjusted
as to permit of the rope B being drawn between the gripping jaws by a
force considerably greater than a more hand-pull applied from outside the cage.
The lever E. E. might extend in either duection from the axis according as
it may be desired to release the handing rope, cham, or iod, by means of an
upward or a downward movement of the rod G.
so
As shown in Figure 1, the parts are so arranged that the releasing action shall
be effected by the pressure of the foot of the lift attendant upon the pedal a, but
it will be obvious that the box C might be fixed to the inner side of the
flooring or to the inner or outer side of the roof of the cage, the only changes in
the mechanism that might be involved being that the lever E might require to

page_text: be reversed so as to project from the opposite side of the casing C to that shewn,
and that the length of the 1od G might require to be altered to suit the various
circumstances.
The locking device illustrated in Figure 3 consists of a pair of gripping
Jaws 1, 1, whereof one, namely I, is fixed to the lift cage D, the other jaw I
being made to slide in guides by a bell crank lever E whose shortei arm
is jointed to it and whose longer aim is so acted upon by a spring Has to
cause the gripping Jaw I to approach the jaw I and thus to grip the handing
rope, chain, oi rod, B the release of the jaws being effected by a pedal or handle
operated from within the cage, as before.
In Figures 4 and 5 the gripping jaws L. L. are formed upon the shorter
arms of a pair of levers M, M, fulcrumed on vertical studs 1. 1. mounted
in a frame fixed to the lift cage D. The longer arms of the levers M, M,
being forced apart by a spring so as to cause the jaws L. L, to gup the
handing ope B or equivalent between them The longer arms of the
levers M, M, are drawn together to release the grip of the jaws L. L, by their
outer ends m, m, being connected to one arm of a bell crank lever E either by a
pair of chains P, P, working over guide pulleys p, p, or by an equivalent pair
of toggle links jointed to the ends m, m. of the levers, the middle joint of the
toggle being coupled to the bell crank by a link or chain.
In Figure 6, as in Figure 3, one of the gripping jaws is a fixture, whilst
the other is composed of a pair of cam-shaped jaws Q. Q', upon two oppositely
directed levers mounted to move in one plane about horizontal fulcrums 7, q, and
coupled by pin and slot connections 4', q, to the crosshead of a rod R acted on by
a spring pressing against the collar 1, so that by the pull of the rod R the
cams Q Q are caused to compress the handing rone B between their gripping
faces and the fixed jaw Q. The grip is released by the movement of the
rod G worked from within the cage acting through the bell crank lever S upon
the rod Rin opposition to the pressure of the spring r SO as to bring the
cams Q Q¹, into the position shewn in dotted lines on the figure. The
duplication of the cam-shaped jaws upon a pair of oppositely directed levers
as described is necessary by the fact that each is efficient to retain the rope
against a pull in one direction only.
Figure shews friction rollers applied to the gripping jaws illustrated in
Figures 1 and 2 These rollers T. preferably of hardened steel, are designed
to reduce wear of the jaws, particularly when a handing chain is used, each roller
being so inserted that only a very small are of its evlindrical surface projects
beyond the gripping face of the jaw, and consequently the efficiency of the grip is
not materially reduced.
It will be obvious that in all cases the action of a weight may be applied
as the equivalent for that of a spring to close the jaws.
Having now particularly described and ascertained the nature of the said inven-
tion, and what manner the same is to be performed, I declare that what I
claim is:-
1. An automatic locking device for the handing rope, chain, or rod, actuating
the controlling gear of hydraulic or other lifts, consisting essentially of a pair
of gripping jaws (whereof one or both
may be movable) mounted upon the
lift cage and adapted to grip the handing rope, chain, or rod, the jaws being
thrown into action by a spring or weight and out of action by a treadle or handle
within the cage acting through lever, wedge, cam, or toggle mechanism, sub-
stantially as specified.
2 An automatic locking device for the handing rope, chain, or rod, of a hydraulic
or other lift, consisting in the combination of two oppositely directed wedge-shaped
jaws adapted to grip the handing rope, chain, or rod, between them and fitted
to slide in correspondingly inclined guides, and of a lever coupled to the jaws so as by
its angular motion to move them in opposite directions, and means of throwing the

page_text: Jaws into action and of releasing their grip from within the cage, substantially as
described in reference to Figures 1 and 2 of the drawings
3. The respective arrangements of automatic locking device constructed and
operating substantially as described and illustrated in Figures 3 to 7 of the
drawings, for the purpose specified.
Dated this 9th day of March 1895.
A. M. & WM CLARK,
53, Chancery Lane, London, Chartered Patent Agents.