Improvements in Safety Gears of Suspended Lifts.
Year: 1895

page_text: Date of Application, 18th Jan., 1895
Complete Specification Left. 16th Oct., 1895-Accepted; 16th Nov., 1895
Improvements in Safety Gears of Suspended Lifts.
JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers, of
Janus Works, Queen's Road, Battersca, in the County of Surrey do.hereby declare
the nature of this invention to be as follows :-
Our invention relates to that class of safety apparatus which depends for its
action upon the opposing pull of two or more ropes attached to rocking or
compensating levers.
Where three or more suspending ropes are employed it is usual to lead them in
one group to the centre of the top of the cage, at which point, they are divided
into two groups, oue being conveyed by means of guide wheels down each side of
the cage to their attachments at the bottom frame...It is also usual to introduce
at that point compensating levers so that irregular stretching or stress among
the ropes of either group would be compensated and distributed, within that
particular group. But if the collective stretching or stress of one group does not
balance that of the opposite group, and if no farther compensation is provided one
set of ropes may have to take an undue share of work, and the sensitiveness of the
safety gear may be impaired.
We provide the required compensation in the following manner. At the point
where the ropes are divided into two groups, instead of mounting the dividing
guide wheels on fixed spindles in the frame, we carry the spindles in two movable
plates free to swing in either direction as required, upon two distinct fulcra situated
above the said guide wheels and fixed to the main suspending frame. These fulcra
are disposed in such positions that the greatest possible compensating effect is
obtained from the minimum movement of the plates. The effect of this arrange-
ment is that if one group of ropes becomes at any time tighter than the other, the
plates swing over toward the former group till the stress is equalised between the
groups. If the plates swing to the left they do so upon the left hand fulcrum, and
the right hand wheels are both lowered and pulled to the left, while the left hand
wheels also move to the left; three contributions to compensation are consequently
given. Swinging to the right would take place upon the right hand fulcrum and
would produce like results.
In the case of two ropes, they are divided at such a compensating device and
then taken direct to the frame of the cage. The motion of the swinging plates in
the act of compensation is then employed to give motion to gripping cams fixed
either above or below the cage-and the said cams would be actuated by the
stretching or breaking of either rope.
In an alternative arrangement two guide wheels in the suspending frame are
separately mounted between separate pairs of swinging plates, the latter being
coupled with a connecting link-with similar results.
In another arrangement we sometimes attach each group of ropes to opposite
ends of a compensating lever fixed at the anchorage end, either to the hydraulic
cylinder, or to the frame or supporting girders of the machine.
Dated this 18th day of January 1895.
JOHN SANDERS STEVENS.
CHARLES GEORGE MAJOR.

page_text: JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers, of
"Janus" Works, Queen's Road, Battersea in the County of London, 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 :-
Our invention relates to. that class of safety apparatus which depends for its
action upon the opposing pull of two or more ropes attached to rocking or
compensating levers.
Where three or more suspending ropes are employed it is usual to lead them in
one group to the centre of the top of the cage a Figs. 1 and 2, at which point b
they are divided into two groups (usually of two ropes each), one group being
conveyed by means of guide wheels down each side of the cage a to their attach-
ments,c c at the bottom frame." It is also usual to introduce at that point' com-
pensating levers ce so that irregular stretching or stress among the ropes of either
group (or pair) would be compensated' and distributed within that particular group.
But if the collective stretching or stress of one group (or pair) does not balance
that of the opposite group, and if no farther compensation is provided, one pair of
ropes may have to take an undue share of work, and the sensitiveness of the safety
gear may be impaired.
We provide the required compensation in the following manner.
At the point b where the ropes are divided into two groups (or pairs), instead of
mounting the dividing guide wheels d d on fixed spindles in the frame e, we carry
the spindles in two movable plates ff provided with slots and free to swing in either
direction as required, upon two distinct fulera g₁ situated above the guide
wheels dd & fixed to the main suspending frame e. These fulcra gl gll are
disposed in such positions that the greatest possible compensating effect is obtained
from the minimum movement of the plates ff. The effect of this arrangement is
that if one group or pair of ropes becomes at any time tighter than the other, the
plates ff swing over toward the former group till the stress is equalised between
the groups
If the plates ff swing to the left they do so upon the left hand
fulcrum g, and the right hand wheels d are both lowered & pulled to the left,
while the left hand wheels d also move to the left; three contributions to com-
pensation are consequently given. Swinging to the right would take place upon
the right hand fulcrum g" & would produce like results.
The safety gear is not shewn but any of the devices described in our Letters
Patent No. 9069 A.D. 1886 may be employed in combination with the invention
hereinbefore described.
In the case of two ropes only being employed Figs. 3 & 4, they are divided at a
point by such a compensating device & then taken direct. and secured to the
frame e of the cage a. The motion of the swinging plates ƒƒ in the act of com-
pensation is then employed to give motion to gripping cams fixed either above or
below the cage & the said cains would be actuated by the stretching or breaking
of either rope.
One method of effecting this is illustrated in Figs. 3 & 4 with an arrangement
of grips on the top of the cage a. The swinging plates ff have extended arms h h
which normally are both in contact with tappet levers ii keyed or otherwise
secured to a shaft k crossing the top of cage, & also carrying gripping cams 11
which run just clear of the guides m m. On the opposite side of each guide is a
gripping plate n n secured to the frame e of the cage. If now either rope should
stretch or break the plates ff must swing out of their normal position, & one of
the arms must push up one of the tappet levers ii, thereby causing the shaft k

page_text: to revolve sufficiently to bring the helically formed cams into contact with the
guides m m and the cains will then grip the guides between themselves & the fixed
plates n n, and the cage will be prevented from descending.
It will be obvious that the cams & their shaft may equally well be mounted
beneath the cage & the motion of the swinging plates conveyed to the shaft by a
simple system of links & levers, or of ropes or chains & wheels, which however
does not need illustration.
Similarly the motion obtained from the swinging plates ff may be used to
actuate any of the devices described and illustrated in our Letters Patent
No. 9069 A.D. 1886 and the applications are so obvious as not to require
illustration.
In an alternative arrangement for four ropes Figs. 5 & 6 two guide wheels d d
in the suspending frame e are separately mounted between separate pairs of
swinging plates ff, the latter being coupled with a connecting link o-with similar
results to those obtained by the device illustrated in Figs. 1 & 2.
In another arrangement we sometimes attach each group of ropes to opposite
ends of a compensating lever fixed at the anchorage end, either to the hydraulic
cylinder, or to the frame or supporting girders of the machine.
We illustrate one form of this arrangement in Fig. 7 in which p is one of the
overhead or frame girders, 9 a rocking beam pivotted on the girder, r one pair of
ropes secured to one end of the rocking beam, and the other pair of ropes secured
to the opposite end.
In some cases it would be more convenient to secure the rocking beam g to the
hydraulic cylinder of an hydraulic lift instead of to the girder or frame. Any
number of ropes from 3 upwards may be divided into two groups and attached to
this device.
We wish it to be understood that we do not confine ourselves precisely to the
applications of our invention herein described, as there are many possible
modifications thereof which are mere mechanical equivalents.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
(1.) In safety gears of suspended lifts the arrangement of swinging plates
substantially as described & illustrated in Figs. 1, 2, 3, 4, 5, & 6.
(2.) In suspended lifts the combination of swinging plates substantially as shewn
in Figs. 1, 2, 3, 4, 5, and 6 with any of the safety gears described in our Letters
Patent No. 9069 A.D. 1886.
(3.) In suspended lifts the safety gear device substantially as described and
illustrated in Figs. 3 & 4.
(4.) In suspended lifts with three or more ropes, the combination of the
anchorage device substantially as described & shewn in Fig. 7 with any safety
gear.
Dated this 16th day of October 1895.
JOHN SANDERS STEVENS.
CHARLES GEORGE MAJOR..