IMPROVEMENTS IN TELESCOPIC FIRE ESCAPES AND IN TELESCOPIC LADDERS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Thomas Vann at the Office of the
Commissioners of Patents on the 3rd October 1878.
THOMAS VANN, the younger, of Birmingham, in the County of Warwick,
Machinist. "IMPROVEMENTS IN TELESCOPIC FIRE ESCAPES AND IN TELESCOPIC
LADDERS."
My Invention consists of the improvements herein-after described in constructing
telescopic fire escapes, by which improvements the fire escape is made very portable,
is readily brought into use, and is very efficient in operation.
Parts of the improvements in telescopic fire escapes may also be applied to tele-
scopic ladders.
In constructing a fire escape according to my Invention I joint to a framing or
platform travelling on wheels a baseboard or support, to which the telescopic ladder
and the mechanism for working the ladder and other parts of the fire escape are
connected. By this jointing of the baseboard or support the collapsed ladder of
the fire escape may be placed horizontally when the fire escape is not in use or
during travelling, or raised into a vertical position when the fire escape is to be
made ready for use. I make the telescopic ladder by preference of three lengths
or parts capable of sliding into and out of one another. Each frame of the compound
ladder is made of trough iron having nearly a semicircular figure in cross section,
the open sides of the trough-shaped frame being situated inwards. The trough
frame of the bottom length or part of the ladder which is fixed to the jointed base-
board described is of a size proper to receive the trough frame of the second or middle
length, and the trough frame of the middle length is of a size proper to receive the
top length of the ladder. By a sliding motion the top ladder or length may be
passed into the second or middle length; and similarly the middle length containing.
the top length may be passed into the fixed bottom length of the ladder.
The telescopic ladder is opened out or elongated and collapsed or closed by the
following mechanism :-
At the top of the jointed baseboard or support carrying the ladder is a horizontal
drum turned by a winch and toothed gearing, and between the said baseboard and
the compound ladder a system of crossing levers of the kind commonly known as
lazy-tong levers is arranged. The top lever of the lazy-tong levers is jointed to
about the middle of the top length or part of the ladder, and the middle of the said
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page_text: lazy-tong levers is jointed to the second or middle length of the ladder. The bottom
lever of the lazy-tong levers is fixed to the baseboard herein-before described. A
wire rope or chain from the horizontal drum described is connected to the system of
lazy-tong levers near the bottom thereof.
When the drum is turned in the proper direction the rope or chain is coiled on it,
and by lifting one of the joints of the lazy-tong levers lengthens or expands the
whole of the said levers. By the lengthening of the lazy-tong levers the ladder is
elongated by the simultaneous sliding of the top length out of the middle length,
and the middle length out of the fixed_bottom length. The telescopic ladder is
thereby rapidly made ready for use. The back or return motion of the drum,
through which the lazy-tong levers are worked, is prevented by a ratchet wheel on
the axis of the drum, with which ratchet wheel a pawl engages. By means of the
said pawl and ratchet wheel the top and middle lengths of the ladder are firmly
fixed at any height to which they may have been raised. The teeth of the ratchet
wheel are so arranged with respect to the motion of the top and middle lengths of
the ladder that when the said lengths are at rest their treads or "rungs" are
opposite one another, and are also opposite the treads or "rungs" of the fixed
bottom length of the ladder. By raising the pawl from the ratchet wheel the drum
may make its return motion, and the lazy-tong levers take their closed or collapsed
position, and the top or middle lengths of the ladder slide into the fixed bottom
length, as before described. When the ladder is in its closed or collapsed position
it may by means of the jointed baseboard be turned down into a.horizontal position
on the travelling platform, and the fire escape thus made ready for travelling.
The upper end of the top length of the ladder is furnished with a horizontal
stage, which is brought near the window of the burning building, from which the
persons to be rescued are to issue. After stepping on to this stage the persons may
readily descend the ladder.
Or for the purpose of saving life and property the following apparatus may be
used in combination with the fire escape-The stage described at the head of the
top length of the ladder may be provided with folding flaps opening upwards. At
each side of the stage is a pulley. Below and parallel with the drum by which
the telescopic ladder is worked is a second drum, on which two wire ropes or chains
are coiled. These ropes or chains are conducted over the pulleys on the stage
described at the head of the ladder, and the ends of the said ropes or chains are
fastened to the sides of a wire basket or receptacle, into which basket the persons
or property to be saved may be placed.
When the ladder of the fire escape is in its elongated state, and the said ladder
has been brought to the window of the burning house the winch of the second drum
is turned so as to wind up the ropes or chains and raise the wire basket to the top
of the ladder. As the basket approaches the stage at the head of the ladder the
handle of the basket strikes against and lifts the flaps of the stage. The persons to
be saved may now place themselves in the basket, and by reversing the motion of
the drum the basket and its contents may be lowered into the street.
Or the basket may be raised and lowered by raising and lowering the ladder by
means of the lazy-tong levers. In this case the raising and lowering is quicker
than when the drum is used.
The said basket may also be used for lowering property from the burning
house.
The arrangement of the parts of the telescopic ladder, of the fire escape, and the
apparatus for working the same may be applied to telescopic ladders for various
purposes.