IMPROVEMENTS IN LADDERS AND FIRE ESCAPES
Year: 1877

page_text: · LETTERS PATENT to William Mitchell, of Brandon, in the County of Suffolk
for the Invention of "IMPROVEMENTS IN LADDERS AND FIRE ESCAPES."
PROVISIONAL SPECIFICATION left by the said William Mitchell at the
Office of the Commissioners of Patents on the 9th July 1877.
WILLIAM MITCHELL, of Brandon, in the County of Suffolk.
IN LADDERS AND FIRE ESCAPES."
"IMPROVEMENTS
My Invention relates to improvements in the construction of ladders and fire
escapes; and as applied to ladders, the improvements have for their object to enable
the ladder, which is constructed in sections, to be more readily lengthened or to be
converted into a pair or pairs of step-ladders, as may be required.
The ladder is constructed in two or more sections, fitting the heel of one in the
top of the other, and pivotted or hinged together at each joint by extensions of a
rung of the uppermost section received in a spring box or bearing in the outermost
section. A rigid joint is ensured by the, rung..next below and extensions of the
rung next above being received in notches in the heel of the one section and in the
top of the other section respectively.
The spring box or bearing above referred to consists of a rod terminating in a
fork, which partly embraces and presses upon the extensions of the pivot rung,
said rod being acted on by a spiral spring, and the whole fitted in a box or other-
wise in the side pieces of the lowermost of the two sections.
This spring rod serves to keep the rungs in the notches above mentioned; but by
raising the forked rod and compressing its spring, the said rungs may be lifted
out of the notches, and the ladder may be folded or doubled to form a pair of
steps.
À ladder constructed of two, four, or more sections may be thus folded at any of
its joints to form a pair of steps of any desired height.
The number of sections is not limited, and may be readily increased or reduced in
number.

page_text: When used as a pair of steps, the spring rod serves to lock the joint where the
ladder is folded, so that no cords or braces are necessary to limit the distance at
which the two parts of the steps are stretched apart.
The top section of the ladder is fitted to slide telescopically in guides fixed to the
section immediately below, this telescopic sliding section being drawn up by cords
or chains attached to it, and passing over pulleys on the section below, and thence
down to a drum turned by a winch handle, and mounted near the base of the
ladder, on which they are wound.
The telescopic sliding section is supported at any height by two arms on a small
cross shaft mounted on the top section but one, the said shaft being provided with a
ratchet and spring detent to hold up the arms out of the way, until released by
pulling a cord connected to the detent. When so released, the arms fall on a rung
of the section in which the shaft is mounted, and the next rung above of the tele-
scopic section comes down and rests upon them.
As applied for the purposes of a fire escape, the ladder as above constructed is
mounted on a base frame on wheels, somewhat like an ordinary fire escape.
The ladder is elevated to any required inclination by pinions on a cross shaft on
the ladder gearing with semicircular racks fixed on the base frame; and this cross
shaft, which may or may not be the axle. of the drum before mentioned for winding
up the telescopic sliding section, may be operated by suitable gearing from the
travelling wheels of the escape, so that the ladder may be replaced at the proper
inclination whilst the machine is travelling.
The drum may also be similarly operated from the travelling wheels by the same
or a different arrangement of gearing, so as to also draw. up the telescopic sliding
section whilst the machine is being conveyed where required.
Suitable clutches should be provided to put the one or other arrangement in or
out of gear, as required.
A canvas tube is attached to a hoop or cage at the top of the sliding section of
the ladder, the said tube having openings at the front at intervals, closed by lacing
or otherwise, so that the tube may be opened at any convenient part for the exit of
the persons descending the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Mitchell in the Great Seal Patent Office on the 9th January
1878.
WILLIAM MITCHELL, of Brandon, in the County of Suffolk.
IN LADDERS AND FIRE ESCAPES."
"IMPROVEMENTS
My Invention relates to improvements in the construction of ladders and fire
escapes in jointed and sliding sections; and the object of my Invention is to enable
the ladder or fire escape to be readily shortened or taken to pieces, and lengthened,
as circumstances may require; and in the case of ladders, to. enable the ladder to be
readily converted into a pair of step-ladders.
The Invention also relates to contrivances in connection with a ladder and fire
escape so constructed, including a canvas shoot with openings at intervals for the
escape of the inmates from a burning building.
In order that the Invention may be more readily understood, I will proceed to
describe it with reference to the accompanying. Drawings, in which,-
Figure 1 represents a front elevation, and Figure 2 a side elevation of a ladder
constructed according to my Invention.
Figure 3 represents a horizontal section of the same on line 1, 2, Figure 1.
Figure 4 represents the two lower sections of the ladder converted into a pair of
step-ladders.
Figure 5 shows details of a device for supporting the sliding section at the
desired height.
Figure 6 represents side and front views of the metal frame, and portions of the
canvas shoot, which is connected to the top of the ladder when used for the purpose
of a fire escapc.
The ladder is constructed of two, three, or more sections, A, B, C, of any con-
venient length, fitting; the foot of the one in the top of the one below. Thus the
section B is rather narrower than the bottom section A, and the side frames fit
between those of the section A, and similarly for the sections B and C.
The sections are pivoted or connected together at each joint as follows:-
Referring to sections A and B, the bottom rung b of the narrower section B is
extended beyond its side frames, and received in spring boxes or bearings D
mounted in the side frames of the wider section A, and a rigid joint is ensured by
notches in the lower end of the section B fitting on the top rung a of the section A,
and by the second rung b' of the section B being extended beyond its side frames,
and received in similar notches in the top of section A.
The spring boxes or bearings D (of which one is shown in detail in Figure 2, the
covering plate being removed) serve to keep the rungs in the notches as above men-
tioned; but by compressing the springs the rungs may be lifted out of the notches,
and the ladder may be doubled or folded to forin a pair of steps, as in Figure 4.
c is an iron rod acted on by a spiral spring, and having one end forked to partly
embrace and press upon the extensions of the pivot rung b. This rod and its spring
are fitted in a metal box let into the side frames of the section A, which are slotted
as at a¹ to allow of the rungs b and b¹ being lifted out of their notches. d, cover
plate, applied as shown, and secured by nuts and screw bolts fixed in the ends of
the rungs b, b¹.
The other sections, B, C, &c. (except the sliding sections hereafter described) are
similarly jointed, and a ladder constructed of two, four, or more sections may thus
be folded at any of its joints to form a pair of steps of any desired height.
When in use as a pair of steps, as in Figure 4, the pressure of the spring rod con
the rung b holds the steps firmly in position, without the use of cords to prevent
the two parts of the steps being stretched too far apart.
The number of sections thus connected and jointed is not limited, and may be
readily increased or reduced, as required.
The section E is fitted to slide telescopically in guides formed of sheet iron bent

page_text: to the form shown in Figure 3, and fixed to the side frames of section C, the section
E passing up in front of and partly between the side frames of section C, as shown.
It is drawn up by chains or cords F attached to it, and passing over pulleys fon a
cross bar fixed on the top of section C, and thence down to a barrel Ġ, mounted in
bearings at the back of section A. This barrel is turned by a winch handle to
wind the chains or cords upon it, and raise the section E. g is a pawl and ratchet
to hold the barrel in any position.
The telescopic section E is supported at any desired height by two arms H on a
small cross shaft h, mounted in arms fixed to section C, and passing in front of
section E.
Referring to the detail, Figure 5, the latter section is represented by dotted lines
in order to show the other parts.
At one end of this cross shaft there is a small spring i, which throws the arms
H down to the dotted position, with their ends resting on the opposite rung of the
section C, when the shaft is released from a spring detent k, which engages with a
tooth on the shaft. The detent is released by pulling a string 1, and the arms H
fall between the side frames of the section E, down to the dotted position shown,
and the rung e of section E next above comes down and rests upon them, as shown
by the dotted lines. On raising the sliding section, the arms H are thrown up, and
retained out of the way by the detent.
The topmost section M is jointed to section E in the same way that the sections
A, B, C, are jointed, but without the spring boxes. This section may or may not
be used, and it forms either an extension of section E, or, by disconnecting the
rungs from the notches and oscillating it on its pivot rung, it may be inclined at
any angle to the ladder, to reach over a gutter or the sloping roof of a house, as
shown in dotted lines, Figure 2.
m, m, Figure 1, safety pins for locking the sections together when uesd as a
ladder.
When applied as a fire escape, the ladder constructed as above described would
be mounted on wheels like an ordinary fire escape, and provided with the usual
frame at right angles to the ladder at the base, and guy ropes to enable the ladder
to be raised from a horizontal to a vertical position in the usual way.
The advantage of this sectional construction for a fire escape is that the sections
can be readily disconnected and taken up a narrow court, where an ordinary escape
could not pass, and then put together for use.
N, Figure 6, is an iron frame fixed to the top of the telescopic sliding section E,
or to any other of the sections of the ladder except the top section M; and O is a
canvas shoot hung from the hook-shaped frame N, when the ladder is applied as a
fire escape.
The improvement in the tube consists in providing a number of openings P in
the front side of the tube, at intervals of a few feet, said openings being closed by
lacing, buttons, or buckles, so that the tube can be readily opened at any convenient
point for the exit of the persons descending; whereas in other escapes, where this
form of tube is used without openings, the persons are necessarily obliged to pass
through the whole length of the tube, although the height of the window from
which they have descended may be much less than the length of the tube.
Having described the nature of my Invention, and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the herein-
before in part recited Letters Patent is,-
1st. In a convertible ladder constructed in sections, connecting the two or more
sections together by the one section pivoting between the side frames of the other
section, and by notches at the top and bottom ends of the two sections engaging
with the rungs next above and below the pivot joint (with or without the spring
boxes herein described), substantially as shown and described for the purpose
specified.
2nd. The combination with the sections jointed or connected together as above
specified of the spring forked rods applied and operating in connection with the

page_text: pivot joint and the slots in which the pivots are received, substantially as and for
the purpose set forth.
3rd. A ladder composed of a number of sections jointed together as above
specified, and a telescopic sliding section raised by ropes or chains, and a winch,
substantially as shown and described.
4th. The combination with the telescopic sliding section of the arms H, fixed on a
cross shaft on the section beneath, and capable of being oscillated so as to rest on
a rung of that section and take under a rung of the sliding section, or be thrown
back out of the way, substantially as shown and described.
5th. The combination with the arms H and shaft h of the spring i, spring detent
k, and cord l, substantially as and for the purpose specified.
6th. A fire escape consisting of a ladder constructed in sections, as herein shown
and described, mounted on wheels, and provided with means for elevating it, and
with a canvas shoot, as described.
7th. A tubular fire-escape shoot, with slits or openings at intervals of its length,
closed by lacing, straps, or other means, capable of being readily unfastened to give
egress, substantially as shown and described.
In witness whereof, I, the said William Mitchell, have hereunto set my hand
and seal, this Third day of January, in the year of our Lord One thousand
eight hundred and seventy-eight.
WILLIAM MITCHELL. (L.S.)