Improvements in Extension Step Ladders.
Year: 1897

page_text: Date of Application, 23rd Mar., 1897-Accepted, 11th Sept.,
1897
COMPLETE SPECIFICATION.
Improvements in Extension Step Ladders.
We, LYMAN FERGUSON and ROBERT HUGHES POLLOCK, residing respectively at
Ithaca, in the County of Tompkins, State of New York, and at 51 South Gay Street,
Baltimore, in the County of Baltimore City, State of Maryland, Gentlemen, both in
the United States of America 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 :-
Our invention has relation to improvements in extension step ladders, and the
object is to produce a simple, durable, and convenient ladder of this class for general
household and inercantile use; and to this end the novelty consists in the
construction, combination and arrangement of the same as will be hereinafter more
fully described and particularly pointed out in the claims.
In the accompanying drawings the same figures of reference indicate the same
parts of the invention.
Figure 1 is a perspective view of our improved extension step ladder;
Fig. 2 is a perspective view, showing the ladder extended;
Fig. 3 is a detail of the hinge joint closed; and Fig. 4 is a similar view with the
joint open.
1 represents the front section, and 2 the back section, one being a counterpart of
the other. The section 1 comprises the side rails 3-31, secured together by the
rectangular rungs 4-4, arranged in horizontal pairs as shown.
The cylindrical ends 5 of said rungs first pass through the orifices 6-6 in the
sheet metal strap 7, and then are closely fitted in the orifices 8-8 in the rails.
These straps have projecting ears 9, which are bent at a right angle over the front
ear, the
and rear edges of the rails, and a finishing screw 10 is inserted through the
front end of the rail, and entirely through the cylindrical end of the rung, making at
once a simple, strong and durable joint.
A portion of the side rails is cut away between each pair of rungs to form oblong
recesses or openings 12, to reduce the weight of the ladder, without in any manner
sacrificing its strength.
The upper ends 13 of the side rails are cut off square, and the contiguous
corners 14 of the front and back sections 1 and 2 are rounded to form a hinge joint,
somewhat similar to a pocket knife blade, and a strap 15 extends up the front edge
across the end 13 around the corner 14, and down the back of each side rail, the
parallel ends of said strap being firmly secured to the rail by bolts 16, 16. This
strap forms a durable brace for the ends of the rails, and effectually prevents them
from splitting.
17-18 represent the side plates firmly secured to the outside of the side rails by
bolts 19-20, a portion of their upper contiguous ends 21 being rounded and formed
with segmental interlocking teeth 22, while their straight ends 23 form abutting
bearings when the sections are opened to form a continuous straight ladder, as shown
in the drawings.
24-24 represent brackets secured to the platform 25, their depending twin.
arins 26-26 being secured to the side rail and plates 17-18 by the bolts 20, which pass

page_text: through the arms 26, the plate, and the side rail, and through the ends of a strap
brace 27 on the inside of the adjoining upper ends of the rails.
By reason of the teeth on the plates meshing, the front and back sections are held
in the same relative position, without regard to their degree of inclination to each other,
and consequently the platform remains at a right angle to a line bisecting the angle
of the two sections.
28 represents a semicircular shelf secured by a hinge 29 to one end of the platform,
and when in use, is held in place by a button on the platform to form a horizontal
continuation of the platform, and when not in use, is folded down out of the
way.
A ladder thus constructed forins a very cheap, strong and durable, as well as safe,
support, and when extended as shown in Fig. 2, the abutting ends 13 of the side rails,
and the right angular ends 23 of the toothed plates, make the ladder as strong and
secure as if the side rails of the two sections were one continuous piece.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. An extension step ladder, comprising two counterpart sections and intermeshing
tooth plates 17-18 having abutting bearings, substantially as and for the purpose
set forth.
2. An extension step ladder, comprising the sections 1 and 2, brackets 24, the
platform 25 secured to the top of said brackets, the plates 17-18 secured to the
upper ends of said sections and formed with intermeshing teeth and abutting bearings,
as and for the purpose set forth.
3. An extension step ladder, comprising two sections, the side rails of which are
provided with toothed plates, and a bracket in which said side rails are hinged, and
which secure the contiguous teeth on the plates in mesh, substantially as shown
and described.
4. An extension step ladder, comprising the sections 1 and 2, having their upper
ends hinged in the bracket 24, the plates 17 and 18 secured to the upper ends of
each section, and provided with a series of interlocking teeth, substantially as shown
and described.
5. An extension step ladder, comprising the sections 1 and 2, provided with the
intermeshing toothed plates 17 and 18, and the platform 25, provided with the
brackets 24, having depending arms 26, in which the upper ends of said sections are
hinged, substantially as shown and described.
6. An extension step ladder, comprising the sections 1 and 2, brackets 24, the
platform 25, secured to the top of said brackets, the plates 17-18 secured to the
upper ends of said sections, and formed with intermeshing teeth and abutting bearings,
substantially as shown and described.
7. In a ladder of the class described, the combination with the side rails, of the
rectangular rungs, having cylindrical outer ends, the strap 7 having angular ears 9,
and the screw 10 passing through said ears, side rail and rung, substantially as shown
and described.
Dated this 23rd day of March 1897.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.