Automatio Speed Regulating and Safety Gear for Hydraulic Lifts and Hoists.
Year: 1895

page_text: Date of Application, 15th Mar., 1895
Complete Specification Left, 16th Dec., 1895-Accepted, 1st Feb., 1896
PROVISIONAL SPECIFICATION.
Automatio Speed Regulating and Safety Gear for Hydraulic Lifts
and Hoists.
1, WILLIAM ARTHUR KER, of 2, Kingdon Road West Hampstead, in the
County of Middlesex, Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to improvements in speed regulating and safety gear for
bydraulic lifts and hoists, either of the direct-acting or suspended types.
My invention has for its object the automatically braking and eventually
stopping of the motion of the lift cage, upon the speed exceeding a predetermined
rate.
For convenience I will describe my invention as applied to a direct-acting lift.
In a previous Application, I have described an arrangement of apparatus designed
to accomplish similar objects and comprising a valve actuated by a piston working
in a cylinder, the two ends of this cylinder being in communication with two points
on one of the pipes, or systems of pipes supplying the lift cylinder with water, the
difference of pressure at the two points due to the friction caused by the water
passing through the pipe, being used to actuate the piston.
In the invention I am about to describe I use a similarly actuated valve; but
after the valve has closed the pipe, upon the speed of the lift still continuing
excessive, cams or dogs attached to the cage are caused to grip the cage guide rails
or other supports, thus arresting the motion of the cage.
To effect this, I attach to the end of the piston rod described above a grooved
wheel moving with the rod; but free to turn upon its axis.
To one of the safety cams underneath the cage, I attach one end of a rope which
passes down under the grooved wheel, up the lift well, over an upper grooved wheel
which is securely attached to the building, down to the side of the cage, where it
passes through one of the cams, and has a weight at the end.
The action is as follows. When the lift is working at its normal speed in one
direction the rope travels with the cage and the safety cams are out of gear.
When the normal speed is exceeded the piston rises, closing the valve, and raising
the grooved wheel on the piston rod, thus reducing the distance between it and the
fixed wheel. The weighed end of the rope then descends, relatively to the cage,
and a clip, fixed upon it, presses the can into gear, arresting the motion of the
cage.
When the speed of the lift in the opposite direction exceeds the normal the
reverse process takes place. The piston descends increasing the distance between
the two wheels, the clip upon the rope pressing against a bracket on the side of the
cage prevents the weighted end of the rope from rising, the end which is fixed to
one of the cams therefore is pulled down, putting the cam into gear, and arresting
the motion of the cage.
It is obvious that many modifications may be made of this arrangement, such as,
connecting the end of the piston rod to a lever carrying the lower grooved wheel,
connecting the cams together so that they may act simultaneously, or doing away
with the valve and using the piston and cylinder to actuate the cams alone.
Dated this Fifteenth day of March 1895.

page_text: COMPLETE SPECIFICATION.
Automatic Speed Regulating and Safety Gear for Hydraulio Lifts
and Hoists.
I, WILLIAM ARTHUR KER, of 2, Kingdon Road, West Hampstead, in the
County of Middlesex, 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 :-
This invention relates to improvements in speed-regulating and safety-gear for
hydraulic lifts and hoists, whether of the direct-acting or suspended types; whereby
braking and stopping the lift-cage is effected automatically upon the speed exceeding
that predetermined.
In the accompanying drawings,
Fig. 1 is a view illustrating one mode of carrying my invention into effect.
Fig. 2 is an enlarged view of the braking and stopping device.
Figs. 3 and 4 are enlarged views taken at right-angles to each other of the
controlling valve and means for actuating the braking and stopping gear.
Figs. 5, 6, 7 and 8 represent various alternative arrangements of my
invention.
Although the present improvements are applicable to hydraulic lifts of both the
above-mentioned types, I will describe, by way of example, the application of my
improvements in the working of a direct-acting lift, i.e., where the lift-cage is
supported upon a ram.
In the Specification to my application for Letters Patent, No. 4444, dated
1st March, 1895, I have described and illustrated apparatus designed to
accomplish similar objects; the same comprising a valve actuated by a piston
working in a cylinder, the two ends of this cylinder being in communication with
two points on one of the pipes, or systems of pipes supplying the lift-cylinder with
water, the difference of pressure at the two points, due to the friction caused by
the water passing through the pipe, being used to actuate the piston.
In carrying out this invention, a similarly actuated valve A is used; but, after
this valve has shut off the supply of the pressure water, upon the speed of the lift
still continuing excessive, cams or dogs B, attached to the lift-cage C, are caused
to grip or engage with the guide-rails c c or other supports whereby the motion of
the cage is arrested. Suitably mounted in the lower extremity of the piston-rod D
is a grooved wheel or pulley E; this wheel or pulley moving with the rod C but
rotating freely on its spindle c. To one of the safety cams B, beneath the lift-
cage C, is attached one end of a rope F, the said rope being led from the cam B
down to the grooved wheel E, up the lift-well, over a grooved wheel G, secured to
the building, then down to the side of the cage C. This end of the rope is
provided with a weighted rod H which passes through the tail-piece 6 of the cam B.
The cam B is maintained in its normal or inactive position by means of a spring 6';
the weights h¹ operating to overcome or to counterbalance the action of the
.spring as hereinafter described.
The operation of the apparatus is as follows:-During the working of the lift
at its normal speed in one direction (for example the down journey), the rope F
travels with the cage C; the safety-cams B being inoperative or out of gear.
When, however, the normal speed is exceeded, and, the ascent of the piston has
effected the closing of the valve A, the wheel or pulley E carried by the piston-
rod D, rises, thus reducing the distance between it and the fixed wheel G, with
the result that the weighted rod H, at the end of the rope F, assisted by the
weight descends relatively to the cage, and, by means of the stop ², presses
the cam B into gear with the guide-rail c, thereby arresting the motion of the
cage.

page_text: On the speed of the lift exceeding the normal in the opposite direction, a
reverse action takes place. The piston-rod D descends, taking with it the wheel
or pulley E, whereby the distance between the wheels E and G is increased.. At
the same time, the rope F has a tendency to raise the rod H; but, owing to the
influence of the weight h¹, the weighted rod is maintained at about its normal
position, the resistance of the spring 6' being overcome by the action of the
piston D. The end of the rope which is attached to the cam B is therefore pulled
down, and the cam brought into operation; the motion of the cage being thereby
arrested. The weight rises and falls with the rod H; but the weight h¹, as will
be seen, comes into operation when it becomes necessary to augment the weight on
the tail-piece b in order to counteract the resistance of the spring b.
weight is preferably heavier than the weight and, instead of being fixed to the
rod H, is supported on a bracket c', a stop h³ on the rod H coming against said
weight and preventing the rising of the rod H. Instead of the stop h³ engaging
with the weight h¹, it may engage with the bracket o¹ and thereby arrest the
movement of the rod H. Or the weight and bracket c' may be employed in
combination..
The
It will be obvious that various modifications in the mode of applying and
working my safety-gear may be made, such for example as, by connecting the end
of the piston-rod to a lever carrying the lower grooved wheel as illustrated in
Fig. 5 by connecting the cams on each side of the cage together so that they may
be operated simultaneously, or by dispensing with the valve A and using simply
a piston and cylinder to actuate the cams, as shown in Fig. 8.
Referring to Fig. 5, the piston-rod D is connected at d with a lever Dx; the
lower grooved wheel or pulley E being carried by the outer end of the lever Dx.
One end of the rope F is attached to the tail-piece 6 of the cam B; the rope
being then led down the well, under the wheel E up to the top of the well, over
the fixed pulley G, and thence to the cage to which it is made fast. The action
will be readily understood. Upon the piston-rod D descending, the outer end of
the lever D is depressed; thereby lengthening the distance between the wheels E
and G, with the result that the tail-piece 6 of the cam B is deflected and the cam
caused to engage with the guide-rails c.
The operation of the arrangement shown in Fig. 6 is somewhat similar, with
the exception that one end of the rope F is attached directly to the upper
extremity of the piston-rod D, while the other end is fixed to the building at the
top of the well. In this modification, the tail-piece b is furnished with a grooved
wheel b over which the rope F passes; the rope passing under another grooved
wheel ex carried by the cage C.
In Fig. 7 a similar mode of operating is shown, but the operating valve A is
disposed horizontally; the rope F passing from the piston-rod D round
pulleys Ex, E°, up the well and over the grooved wheel 6* on the tail-piece b,
then under the wheel c* to the top of the well where it is secured.
The operation of the arrangement shown in Fig. 8 will be apparent on reference
to the drawing. Instead of a piston and valve for actuating the safety-gear, the
piston and cylinder alone are employed for this purpose; the pressure-water
passing through the cylinder.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim :-
--
1. The improved means for automatically controlling the speed of hydraulic
lifts and hoists, arranged substantially as herein described and comprising a valve
operated by a piston, the opposite sides of which are exposed to two different
pressures occurring at two different points in the pressure-system, and whereby
the supply of pressure-water to the power-cylinder is restricted or shut off, a
safety appliance attached to the cage being by the same agency brought into
action.
2. The combined automatic speed-regulating and safety-gear for hydraulic lifts

page_text: and hoists, arranged and operating substantially as described with reference to
Fig. 1, Fig. 5 or Fig. 8 of the accompanying drawings..
3. For actuating safety-gear of the kind herein referred to, the employment of
a piston enclosed in a cylinder and rendered operative upon the difference of
pressure to which its opposite sides are exposed becoming excessive, substantially
as herein described.
4. In safety-gear for hydraulic lifts and hoists, the combination with cams such
as B, of a differential-pressure-actuated piston, suitably connected therewith and
arranged to operate substantially as set forth.
5. In safety-gear for hydraulic lifts and hoists, the combination with cams, such
as B, of a differential-pressure-actuated piston and rod D, a lever Dx, rope F
and wheels or pulleys E, G, substantially as and for the purpose set forth.
D
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