An Improved Folding Ladder.
Year: 1892

page_text: Date of Application, 14th May, 1892
Complete Specification Left, 14th Feb., 1893-Accepted, 22nd Apr., 1893
PROVISIONAL SPECIFICATION.
An Improved Folding Ladder.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from La Société Conti,
Radice, Guelfi & Rigoni, of 8, Via Urso, Milan, in the Kingdom of Italy,
Engineers,) to be as follows:-
This invention relates to an improved folding ladder which can be unfolded and
raised or folded and lowered with certainty and rapidity at a single operation ; the
ladder, when folded, occupying very little space.
Each side of the ladder is composed of a double row of bars arranged in pairs,
each pair being pivoted together by a central pin which extends from one side of
the ladder to the other. The ends of the arms of one pair are also jointed to the
ends of the arms of the next pair. The central pins serve as steps or rounds, the
other steps or rounds connecting the inner rows of bars. The ends of the bars are
so shaped that when the ladder is fully extended, the sides of the ladder formed by
the bars are flat without any break in the continuity. The ladder is wider at the
base than at the extreme end. Each pair of bars in the double row forming one
side of the ladder are kept apart by a boss or collar concentric with the central pin
in each pair, and by a boss or collar concentric with each joint-pin at the ends of
the arms.
Each central pin is preferably in the form of a bolt having at one end a
fixed head and at the other end a nut; a spring being placed between the nut and
the adjacent bar. The lowest outer bar on each side of the ladder is furnished
with a trunnion supported in a bearing on the carriage. The carriage serves as a
base for the ladder, and enables it to be moved from place to place. A chain
for actuating the ladder is connected to the free end of each lowest inner bar;
these chains passing to and being coiled upon a shaft arranged transversely beneath
the carriage. This shaft carries a spur-wheel, with which a pinion on an axle
operated by a hand-lever engages. Each chain passes from the extremity of the
bar over a rounded strut projecting from the bar, so as to prevent the chain getting
into such a position that a pull on the chain would act with insufficient leverage to
rotate the bars on the central pin. As the free ends of the lowest inner bars
approach the free ends of the lowest outer bars, the opposite ends of these bars also
approach one another, and finally meet after passing through an angle of 180° or
thereabouts. This movement is also communicated to the bars to which the lowest
bars are jointed, and from these to the next, and so on to the end of the ladder.
The ladder closes under the influence of gravity, the action being under control by
means of the hand-lever. The lowest bars are locked together by a safety bolt
passed through them in order to prevent the ladder closing prematurely owing to
the breakage of a chain or otherwise. The outer bars on each side may be
strengthened by rods jointed together and to the bars, which they overlie; these
rods turning inwards while the ladder is being closed and outwards while it is being
opened. The rods are so arranged that the closing of the ladder is not interfered
with. The free ends of the lowest outer bars are provided with levers connected to
a screw-threaded rod, which passes through a screw-threaded collar pivoted to the
carriage. This rod can, with the aid of bevel-gearing, be turned by means of a
hand-wheel. By turning the rod, the lowest outer bars-and consequently the
whole ladder-can be caused to turn on the trunnions above referred to; the
inclination of the ladder being thereby readily varied to any desired extent within
an angle of about 90°

page_text: Instead of varying the inclination of the ladder in the manner described,
horizontal screw-rods rotating in bearings on the carriage, and passing through
moveable screw-threaded slides, may be employed; the slides being linked to the
ladder. The screw-rods are rotated through bevel-gearing and hand-wheels; the
rotation of the rods causing the slides to move so as to vary the inclination of
the links and consequently of the ladder.
The forward part of the carriage to which the ladder is pivoted is furnished with
two wings composed of rods, which can be turned in a horizontal plane, or
disconnected and folded over on the carriage. The extremities of these wings,
which may be provided with adjustable rollers, bear against the ground, and serve
as additional supports for the ladder when requisite.
Dated the 13th day of Mar 1809
G. G. M. HARDINGHAM.
COMPLETE SPECIFICATION.
An Improved Folding Ladder.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from La Société Conti,
Radice, Guelfi & Rigoni, of 8, Via Urso, Milan, in the Kingdom of Italy,
Engineers,) 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 an improved folding ladder, which can be unfolded and
raised, or folded and lowered, with certainty and rapidity at a single operation ;
the ladder, when folded, occupying very little space.
In the accompanying drawings, which serve to illustrate the present invention,
Fig. 1 is a diagram representing in side elevation the ladder when fully opened;
an intermediate position being shown in broken lines, and the closed position in
dotted lines.
Fig. 2 is a side elevation representing the lower part of the folded ladder.
Fig. is a side elevation illustrating modified mechanism for varying the
inclination of the ladder; Fig. 2ª being a corresponding plan.
Fig. 3 is a side elevation of the unfolded ladder; Fig. 4 being a corresponding
front elevation.
Figs. 34 and 44 are detail views showing a modified way of jointing the bars.
Figs. 5 and 6 are detail views representing the preferred way of jointing the rods
or bars.
Fig. 7 illustrates the manner in which the ladder is jointed to the carriage.
Fig. 8 represents the safety bolt.
Each side of the ladder is composed of a double row of bars arranged in pairs;
each pair being pivoted together by a central pin p, which extends from one side of
the ladder to the other, so as to serve for two pairs of bars. The ends of the
arms of one pair are also jointed (as indicated at s in Fig. 2) to the ends of the
arms of the next pair. The joint-pins extend across the ladder from the joint ou
one side to the corresponding joint on the other. The central pins and the joint-
pins serve as steps or rounds; the requisite number of steps or rounds being
completed by other steps or rounds which connect the inner rows of bars. The
ends of the bars are shaped as shown at e so that, when the ladder is fully extended,
the sides of the ladder formed by the bars are flat without any break in the
continuity. The ladder is wider at the base than at the extreme upper end. Each
pair of bars in the double row forming one side of the ladder are kept apart by a
boss or collar (Figs. 5 and 6) concentric with the central pin p pertaining to that
pair, and by a boss or collar concentric with each joint-pin at the ends of the arms.
Each central pin is preferably in the form of a bolt having at one end a fixed head.
and at the other end a nut. A spring (Figs. 5 and 6) is placed between the nut on

page_text: the end of each joint-pin and the adjacent bar. The lowest outer bar on each side
of the ladder is furnished with a trunnion o supported in a bearing on the carriage.
The carriage serves as a base for the ladder, and enables it to be moved from place
to place. A chain for actuating the ladder is connected at R by means of the
rod y to the free end of each lowest inner bar; these chains passing to and being
coiled upon a shaft a° arranged transversely beneath the carriage. This shaft.
carries a spur-wheel I, with which a pinion on an axle operated by a hand-lever 10
engages. Each chain passes from the extremity of the bar over a rounded strut m
projecting from the bar, so as to prevent the chain getting into such a position that
a pull on the chain would act with insufficient leverage to rotate the bars on the
lowest central pin. As the free ends of the lowest inner bars approach the free
ends of the lowest outer bars, the opposite ends of these bars also approach one
another, and finally meet after passing through an angle of 180° or thereabouts.
This movement is also communicated to the bars to which the lowest bars are
jointed, and from these to the next, and so on to the end of the ladder. The ladder
closes under the influence of gravity; the action being under control by means of
the hand-lever 6°. The lowest bars are locked together by a safety bolt G passed
round or through them in order to prevent the ladder closing prematurely owing to
the breakage of a chain or otherwise. The outer bars on each side may be
strengthened by rods f, and e jointed together and to the bars, which they
overlie; these rods turning inwards while the ladder is being closed, and outwards
while it is being opened. The rods are so arranged that the closing of the ladder
is not interfered with. The free ends of the lowest outer bars are provided with
arms or levers connected to a screw-threaded rod T, which passes through a screw-
threaded collar pivoted to the carriage. This rod can, with the aid of bevel-gearing u,
be turned by means of a hand-wheel V. By turning the rod T, the lowest outer
bars and consequently the whole ladder-can be caused to turn on the trunnions o;
the inclination of the ladder being thereby readily varied to any desired extent
within an angle of about 90°. If preferred, a separate screw-rod T may be applied
to each arm of the lowest outer bars, and the double bevel-gearing u may be turned
by the same hand-wheel.
Instead of varying the inclination of the ladder in the manner described, horizontal
screw-rods c d rotating in bearings on the carriage, and passing through movable
screw-threaded slides mo, may be employed; the slides being connected by links a bi
to the ladder. The screw-rods c d are rotated through bevel-gearing and a
hand-wheel ex or hand-wheels; the rotation of the rods causing the slides m° to
move so as to vary the inclination of the links a b and consequently of the ladder.
One of the positions assumed by the right-hand link and slide is indicated at a' b¹m³
(Fig. 1A).
The forward part of the carriage to which the ladder is pivoted is furnished with
two wings M N composed of rods, which can be turned in a horizontal plane (as
indicated at M N") about a vertical axis g h, or disconnected at and folded over
about as a pivot on to the carriage, as indicated at g¹ M' N'. The extremities of
these wings, which may be provided with adjustable rollers K, bear against the
ground, and serve as additional supports for the ladder when requisite. Each
roller K is made adjustable as regards height in order to allow for inequalities of
the ground.
In the modified construction shown in Figs. 34 and 4ª, the springs r (Figs. 5
and 6) are dispensed with. The flat surfaces a* b*, o* dx and e* f* are all parallel
and at right angles to the pivot. p* and q* are arcs which are in contact in the
plane g, and keep the parts in the proper relative positions while they are
rotating.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved folding ladder constructed or operating substantially as described
with reference to the accompanying drawings.

page_text: 2. A folding ladder comprising two sets of jointed bars connected together
substantially as herein described, the same being unfolded by means of a hand-wheel
or crank and suitable intermediate mechanism.
3. A folding ladder comprising two converging sets of jointed bars connected
together and mounted on a carriage furnished with wings or additional supports,
substantially as described with reference to the accompanying drawings.
4. A folding ladder comprising two converging sets of jointed bars, connected
together by pivot-pins, joint-pins and other rounds of the ladder, and mounted on a
carriage furnished with means for varying the inclination of the ladder, substantially
as described with reference to the accompanying drawings.
5. In a folding ladder, the employment of spring-connections, substantially as
described with special reference to Figs. 5 and 6 of the accompanying drawings, for
permitting the rotation of the individual bars notwithstanding the convergence of
the sides of the ladder.
6. In a folding ladder, the employment of arcs, substantially as described with
special reference to Figs. 3 and 4, for keeping the parts in their proper relative
positions during rotation, thus enabling spring-connections to be dispensed with.
7. In a folding ladder, the employment of mechanism, substantially as described
with special reference to Figs. 2 and 3 of the accompanying drawings, for unfolding
the ladder.
8. In a folding ladder, the employment of mechanism, substantially as described
with special reference to Figs. 2 and 3 of the accompanying drawings, for varying
the inclination of the ladder.
9. In a folding ladder, the employment of mechanism, substantially as described
with special reference to Figs. 14 and 2ª of the accompanying drawings, for varying
the inclination of the ladder.
10. In a folding ladder, the employment, substantially as described with reference
to the accompanying drawings, of side rods f, l and h.
11. In a folding ladder, the employment, substantially as herein described, of a
safety bolt G for locking the side bars together.
12. In a folding ladder, the employment, substantially as described with reference
to Figs. 1 and 24 of the accompanying drawings, of wings or additional supports
adapted for movement in a horizontal plane or for being disconnected and turned
up on to the carriage when not required.
Dated the 14th day of February 1893.