IMPROVEMENTS IN SAFETY APPLIANCES FOR ELEVATORS
Year: 1883

page_text: LETTERS PATENT to Arthur William Lovell Reddie of the Office for Patents
66 Chancery Lane in the County of Middlesex, Patent Agent, for an Invention
of IMPROVEMENTS IN SAFETY APPLIANCES FOR ELEVATORS communicated
to him from abroad by Robert Augustus Chesebrough of the City and State
of New York, United States of America
PROVISIONAL SPECIFICATION left by the said Arthur William Lovell
Reddie at the Office of the Commissioners of Patents on the 21st August
1883.
ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents 66 Chancery Lane
in the County of Middlesex, Patent Agent, IMPROVEMENTS IN SAFETY APPLIANCES
FOR ELEVATORS" [communicated to him from abroad by Robert Augustus
Chesebrough of the City and State of New York, United States of America]
This invention relates to the class of appliances for elevators which are designed
to check or retard the fall of the elevator, car, cab, or platform when the hoisting
rope breaks, and thus prevent injury to the occupant or occupants of said car, cab
or platform,
The stop pawls, dogs or clamps with which the car or cab is frequently provided
and which are designed to engage with racks or posts in the elevator shaft are
commonly thrown into action by a spring or springs, and are not always reliable,
and in any case if they act properly they check and stop the car or cab suddenly,
and are thus subjected to ernormous strain and shock.
The object of this invention is to provide a safety appliance which shall be more
certain in its action, which shall not be liable to get out of order or become
inoperative, and which will retard the fall of the car or cab to such an extent as
to remove all danger to the occupants and yet so gradually as to prevent any
considerable shock or strain upon the said appliance.
To this end the invention consists in the combination with an elevator shaft
and a car, cab or platform working therein, of a cylinder or tube and a plunger
contained therein, one fixed at the bottom of the shaft and the other attached to
the car cab or platform in such manner that the rise and fall of the car, cab or

page_text: platform will cause a reciprocating movement between said cylinder or tube and
plunger; and a vent; aperture or passage through which air or other elastic fluid
may enter or leave the cylinder. This vent aperture or passage is made of such
size or its size is so regulated that the air or other elastic fluid can flow to or from
the cylinder in sufficient volume to enable the car, cab or platform to be raised and
lowered without any increased resistance, but of such small size that when the car
cab or platform falls, the piston or plunger will tend to expel the air or elastic
fluid from the tube or cylinder much faster than it can escape through the vent,
and thus a cushion of compressed air or elastic fluid will be formed in the cylinder
to gradually retard the fall of the car, cab or platform and thus prevent injury to
the occupants thereof.
AL
For buildings of moderate height or in places where the ground can be easily
bored to receive a cylinder or tube, a single long cylinder or tube at the bottom
of the shaft, and a single plunger attached to the car cab or platform will suffice,
but for higher buildings a telescopic system of tubes and plungers may be used
and in the very highest buildings the tube or plunger having the greatest extension
may
be connected with the car, cab or platform by a chain or rope so as to allow
the said car to move some distance above it, and may have a buffer at its upper
end against which the car, cab or platform will strike as it commences to fall.
The safety appliance may be used alone or in addition to the usual safety
appliances above described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Arthur William Lovell Reddie in the Patent Office on the 21st
. February 1884.
:
ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents 66 Chancery Lane
in the County of Middlesex Patent Agent "IMPROVEMENTS IN SAFETY APPLIANCES
FOR ELEVATORS a communication to me from abroad by Robert Augustus
Chesebrough of the City and State of New York United States of America.
"
The Invention relates to the class of Appliances for Elevators which are designed
to check or retard the fall of the Elevator Car, Cab:ór Platform when the hoisting
rope breaks and thus prevent injury to the occupant or occupants of said Car, Cab
or Platform: The stop pawls dogs or clamps with which the Car or Cab is
frequently provided and which are designed to engage with racks or posts in the
Elevator Shaft are commonly thrown into action by a spring or springs and are
not always reliable, and in any case if they act properly they check and stop
the Car or Cab suddenly, and are thus subjected to enormous strain and shock.
The object of my Invention is to provide a safety appliance which shall be more
certain in its action, which shall not be liable to get out of order or become
inoperative, and which will retard the fall of the Car or Cab to such an extent as
to remove all danger to the Occupants and yet so gradually as to prevent any
considerable shock or strain upon the said appliance.
To this end the Invention consists in the combination with an elevator shaft and
a Car Cab or Platform working therein, of a Cylinder or tube and a plunger
contained therein one fixed at the bottom of the Shaft and the other attached to
the Car, Cab or Platform in such manner that the rise and fall of the Car, Cab or
Platform will cause a reciprocating movement between said Cylinder or tube and
plunger, without the plunger leaving the Cylinder, and a vent, aperture or passage
through which air or other elastic fluid may enter or leave the Cylinder. This
vent, aperture or passage I make of such size, or so regulate its size that the air or
other elastic fluid can flow to or from the Cylinder in sufficient volume to enable
the Car, Cab or Platform to be raised and lowered without any increased resistance
but of such small size that when the Car Cab or Platform falls the piston or
plunger will tend to expel the air or elastic fluid from the Cylinder or tube much
faster than it can escape through the vent, and thus a Cushion of compressed air
or elastic fluid will be formed in the Cylinder to gradually retard the fall of the
Car, Cab or Platform and thus prevent injury to the Occupants thereof
For Buildings of moderate height, or in places where the ground can be easily
bored to receive a Cylinder or tube a single long Cylinder or tube at the bottom
of the Shaft, and a single plunger attached to the Car, Cab or Platform will suffice;
but for. higher buildings a telescopic system of tubes and plungers may be used
and in the very highest buildings the tube or plunger having the greatest.
extension may be connected with the Car Cab or Platform by a Chain or rope so
as to allow the said Car to move some distance above it, and may have a buffer at
its upper end against which the Car Cab or Platform will strike as it commences
to fall.
A valve in the plunger which opens as the plunger rises, and closes.a as it falls,
may in some cases take the place of the vent, aperture or passage above named..
The safety appliance may be used alone or in addition to the usual safety
appliances above described.
1
".
> :
In the accompanying drawing Fig. 1 is a sectional elevation of an elevator.
showing the appliance in its simplest form, the building not being very high.;.

page_text: Fig 2 is a similar section of an Elevator in a higher building; Fig 3 is a similar
section of an elevator in a still higher building; and Fig 4 is a sectional view of a
Cylinder and a plunger having a valve in it adapted for the use of liquids. Similar
letters of reference designate corresponding parts in all the Figures.
In all the Figures A designates the elevator shaft and B designates the Cab, Car
or Platform which is capable of being raised and lowered therein-To the Car or
Cab B is attached the hoisting rope Č which passes over sheaves or wheels C¹ and
thence to the mechanism whereby the Car or Cab is raised and lowered.
I will first describe the construction shewn in Figure 1 which represents a low
building having only four floors D.
In the bottom of the Shaft A is a tube or Cylinder E which is sunk in the
ground and in which is fitted a piston or plunger a, and its rod, a¹. The said rod
is attached to the bottom of the Car or Cab B, and as the latter is raised and
lowered the piston or plunger is reciprocated in the tube or Cylinder E without
ever leaving the Cylinder.
From the lower end of the tube or Cylinder E, a pipe 6 leads upwards to the
shaft. This pipe forms a vent passage and as the piston or plunger a is reciprocated
in the tube or Cylinder air will be drawn into the Cylinder and forced out of the
Cylinder through the pipe or passage b.
The pipe or passage b is large enough to allow air to be drawn into the Cylinder
or forced out therefrom with sufficient rapidity to allow of the piston or plunger a
moving freely up and down in the normal operation of the Car or Cab B, but if
the hoisting rope C should break, or if from any other cause the Car or Cab should
fall, the piston or plunger will compress the air in the Cylinder owing to the small
size of the vent pipo b and thus an air cushion will be formed which will gradually
retard the fall and prevent injury to the Occupants.
The Cylinder E has at the top a guide or stuffing Box c through which the rod or
tube a works and the piston or plunger may be provided with any suitable
packing not here shown.
The Cylinder E should have near the top an air vent so that the movement of
the piston or plunger will not be impeded by the compression or rarification of air
in the upper part of the Cylinder. I have shewn such a vent at c².
The rod amay be solid or consist of a tube
In Fig 2 I have represented six floors, D, and because of the height of the
Shaft and consequent length of Cylinder or tube that would be required it might
be impracticable or at least difficult to employ a single Cylinder or tube and
plunger as shown in Fig 1, I fix à Cylinder E in the bottom of the Shaft A, and
the piston or plunger a of this Cylinder is attached to a second Cylinder E' within
which works a second piston or plunger a attached to the lower end of a rod or
tube a¹. The upper ends of the Cylinders EE are provided with heads or guides c,
and in this case the air vent b is at the top of the rod or tube a¹, and is provided
with a cock or valve for regulating the passage of air-This valve is adjusted so
that it will permit the inflow and outflow of air to and from the Cylinders with
proper rapidity so long as the Car or Cab moves at a normal speed, but in case the
Car or Cab falls the air not having a sufficiently free escape through the vent b,
will be compressed in the Cylinders and will retard the movement of the pistons
or plungers a a³ sufficiently to break the fall and provent accidents.
In the top of the Cylinders E E are air vents c for the purpose above
described.
In Fig 8 I have represented eight floors D and two Oylinders E E² in addition
to the fixed Cylinder E-The Cylinder E¹ carries a piston or plunger a, fitting the
Cylinder E. The Cylinder E' carries a piston or plunger.a?, fitting the Cylinder E';
and the rod or tubo a carries a piston or plunger a-The rod or tube a¹ in this
case is not connected directly with a Car or Cab, B, but is connected therewith by
a chain, rod or similar connection, at, so as to permit the Car or Cab to continue
its upward movement aftor the telescopic system of Cylinders has been extended
to its full height.

page_text: At the upper end of the rod or tube a' is a yielding buffer as to lessen the shock
when the car or cab strikes it, and at the upper end of said rod or tube is a vent b
controlled by a valve. So long as the car or-cab moves at normal speed the air
to and from the cylinders will pass through the vent-b with sufficient freedom to
prevent any material resistance being offered; but in case the car or cab falls;
the air will be compressed in the cylinders and the fall of the car or cab will
be retarded. .
The valve and vent 6 may advantageously be near the car or cab, as shewn in
Fig: 2, for then a governor may be carried by the car or cab, and if the speed of
the latter increases beyond the desired point the vent valve 6 will be more or less
closed and so the air prevented from escaping from the cylinder.
In the top of the cylinders E, EL, E³, are air vents, o¹. for the purpose above
described
In order to place the lower tube or cylinder in place a hole may be bored or
drilled therefor as is done in sinking a well.
In lieu of air any other elastic fluid might be employed.
:
In Fig 4 I have represented a form of apparatus in which the piston or plunger
is provided with a downwardly opening valve.
E designates the cylinder which may be fixed at the bottom of an elevator
shaft and a is the piston or plunger which may be attached by a rod a' to the
bottom of the car, cab or platform so that the rising and falling of the car, cab or
platform will cause the piston or plunger to reciprocate in the cylinder.
The piston or plunger a is provided with a downwardly opening valve a³ which
opens as the piston ascends and closes as it descends.
In an elevator in which the lift is moderate, and speed of movement is not
important water may be used instead of an elastic fluid, in which case the water
remains constantly in the cylinder and the piston head or plunger is made rather
smaller so as to allow it to pass slowly up and down through the water, the valve
opening as the piston rises and closing as it descends
The Inventor is aware that it is not new to raise an elevator car or cab by
means of a hydraulic cylinder and a plunger working therein by water pressure,
and he is also aware that a telescopic system of cylinders has been employed and
worked by water pressure for a like purpose.-Heretofore however the elevator
car or cab has been operated by such cylinders and plungers, while in my appliance
the plunger or plungers are operated from the car or cab and they have no function
whatever until the hoisting rope breaks.
Having now set forth the nature of the said Invention of "Improvements in
Safety Appliances for Elevators" as communicated to me by my Foreign Corre-
spondent and explained in what manner the same may be carried into practical
effect I wish it to be understood that I claim:
First: The combination with an elevator shaft and a car or platform working
therein, of a cylinder and plunger, one fixed at the bottom of the shaft and the
other attached to the car or platform in such manner that the rise and fall of the
car or platform will cause a reciprocating movement between said cylinder and
plunger without the plunger leaving the cylinder, and a vent aperture or passage
through which air or other elastic fluid may enter and leave the cylinder, the
whole being independent of the mechanism for raising and lowering the car or
platform and forming a safety appliance which always extends from the bottom
of the car or platform for retarding the fall of the car substantially as and for the
purpose described.
Second The combination with an elevator shaft and a car or platform working
therein, of a telescopic system of tubes or cylinders and plungers between the
bottom of said shaft and the car or platform, and provided with a vent aperture
or passage through which air or other elastic fluid may enter and leave the system,
the whole being independent of the mechanism for raising and lowering the car
or platform and forming a safety appliance to retard the fall of the car substantially
as described

page_text: Third: The combination with an elevator shaft and a car or platform working
therein of a telescopic system of tubes or cylinders and plungers having a vent
aperture or passage through which air or other elastic fluid may enter and leave
the system, and attached to the car or platform by a chain or other connection so
as to permit the upward movement of the car or platform beyond the telescopic
system, the whole being independent of the mechanism for raising and lowering
the car or platform and forming a safety appliance to retard the fall of the car or
platform substantially as described.
Fourth: The modification of the Invention described with reference to Fig: 4.
In witness whereof I the said Arthur William Lovell Reddie have hereunto set
my hand and seal the twentyfirst day of February in the year of our Lord One
thousand eight hundred and eighty four.
ARTHUR W. L. REDDIE. (L.S.)