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Патент USA US2405269

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f 2,405,269
Filed March 13, 1945 v
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Patented Aug. 6, 1946
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Alexander L. Prutsman, Portland, Oreg.
Application March 13, 1945, Serial No. 582,502
1 Claim.
(Cl. 228-63)
This invention relates in general to ladders hav
making and arranging the cooperating parts in
. ing adjustable extensions at the bottoms of the
sidesJ or legs to enable one side or leg or stile to be
extended below the other so that the ladder can
be brought into desired upright position even
though standing on sloping ground.
An object of the present invention is to provide
the manner hereinafter briefly described with
reference to the accompanying drawing.
In the drawing:
Fig. l is a drawing, in isometric perspective, o
an adjustable ladder embodying my invention;
Fig. 2 is a front elevation, partly in section, of
a simple attachment for an ordinary ladder by
the lower portion of the ladder of Fig. l, drawn to
means of which either leg can be caused to ex
a larger scale, and showing the ladder adjusted
tend below the other, so as to enable the bottom 10 for uneven ground;
of the ladder to be adjusted for the sloping or
Fig. 3 is an elevation of the adjustable attach-v
uneven surface of the ground on which the ladder
ment alone, showing the inside face. this View
is obliged to stand.
Several attachments for ladders, which are de
being assumed to be taken along the line 3-3 of
Fig. 2;
signed to accomplish the same general object, 15
Fig. 4 is a fragmentary elevation of the outside
have been invented. These, however, do not ap
face of the ladder leg adjacent to the adjustable
pear to have been introduced into public use to
attachment, the view being taken as indicated by
any considerable extent. The reasons for their
the arrows ¿l-ê in Fig. 2; and
lack of widespread use I believe to be due to the
Fig. 5 is a fragmentary iront elevation drawn
fact that such attachments are more or less 20 to a reduced scale, of the same ladder, but show
expensive and are quite troublesome to install
ing the bottom of the ladder adjusted so as to rest
and use. As a result, persons using ladders pre
on ground sloping in an opposite direction from
fer to follow the old, but less satisfactory and
that indicated in Fig. 2.
more dangerous, method of placing blocks under
In all the figures the same parts »are indicated ‘
one leg cr the other to compensate for the un 25 by the same'reference characters.
evenness of the ground. Some of the devices
In carrying out my invention I use an ordinary
which have been invented for this purpose ernn
ladder comprising the usual runas 22 and legs or
ploy an adjustable attachment which is required
Stiles IG and I I, and first cut off a portion of the
to be changed from one leg of the ladder to the
bottom end of one of the legs below the bottom
other, depending upon which leg is required to 30 rung. Thus, in the ladder of Figs. 1, 2 and 5 a
be made longer, thus necessitating a certain
portion has been cut oif from the bottom of the
amount of time and inconvenience in making the
leg l0, causing this leg to be considerably shorter
desired adjustment. Other devices which have
than the other leg II of the ladder. It does not
been invented for the saine purpose seek to re
matter which of the two ladder legs is shortened
duce this amount of time and inconvenience by 35 in this manner.
having adjustable attachments on the ends of
both legs of the ladder. However, this in turn
Near the bottom of the shortened leg I0 a small
metal plate I2 is attached on the outer face, as
means an increased cost for each ladder.
shown in Figs. 2 and 4. This small plate I2 is
A particular object of the present invention is
preferably attached to the outer face of the lad
to provide an adjustable ladder in which the 40 der leg by a pair of screws I3, the heads of which
adjusting attachment is required to be placed on
are counter-sunk in suitable recesses in the plate
one leg only and need not be removed from that
I2. The outer face of the plate I2 is serrated
leg regardless of the direction in which the ground
or formed with teeth, as indicated in Fig. 2. In
the shortened leg I0 »of the ladder a pair of
A further object of this invention is to provide 45 holes are bored and a pair of clamping bolts |14
a simple, inexpensive attachment which can be
and I5 are inserted through these holes, the holes
easily and quickly installed on any ordinary ladder
and bolts lbeing in alignment and being arranged
and which attachment, when combined With the
along the center line of the leg. With these
ladder, will result in producing the desired ad
changes the ladder is now ready for the adjust
50 able attachment.
justable ladder.
I attain the above mentioned objects and inci
The adjustable attachment I6 is formed pref
dental advantages by using an ordinary ladder
erably from a piece of material of the same ap.-V
and ñrst making one leg of the ladder shorter
proximate cross-section as the ladder legs. The
than the other and then installing an adjustable
adjustable attachment I6 has longitudinal slots
leg extension on the shorter leg, and further, _by 55 I'I and I8, both of the same length, which are
in alignment along the longitudinal center line
of the piece. As apparent from the drawing,
the clamping bolts I4 and> I5 extend through
these slots and the slots are of suflicient length
to enable the adjustable attachment I6 to be
arranged on the ladder leg Iß with the bottom
end of the attachment I6 located below or above
the bottom of the end of the other ladder leg II
tachment I6 is raised, instead of being lowered,
until the bottom of the attachment is of sum
cient distance above the bottom of the ladder leg
II to accommodate the ladder to the ground sur
Thus, with my invention it is not necessary to
transfer an adjustable attachment from one leg
of the ladder to the other under any conditions,
nor isvit Ynecessary to provide ari-adjustable at
ends of theattachmentglß and leg Il to any> lo tachment for both legs Vof the ladder. :Further
a suñicientvdistance l,to accommodate the bottom »
ordinary differences in ground surface levels.
more, my invention can -be carried out with any
A recess I^9 is formed in the face of the ad
justable attachment I6, the recessed face being
ordinary ladder. The additional parts required
i are simple and inexpensive in themselves and
adjacent to the outer face of the ladder leg III.A -
very» little work or expense is required with my
A plate 20, which is serrated or formed With teeth
invention inchanging the ordinary ladder into
to correspond with and engage the teeth or ser
an adjustable ladder suitable for all practical
rated surface of the plate I2, is secured'in the
recess I9 by suitable counter-sunk screws. The
depth of the recess I9 is made equal to the com
An adjustable ladder comprising, a pair of legs
bined thicknesses of the two plates I2 and 29, 20 connected by rungs, one of said legs extending
when the plates have their teeth in engagement,
for a shorter distance below the bottom rung
as shown in Fig. 2, so that the opposed faces of
than the other leg, a plate attached to the out
the adjustable attachment I6 and ladder leg ID
side face of said shorter leg, an adjustable vat
will contact each other. Suitable washers and
tachment moutned on the outside face of said
clamping nuts 2| are placed on the outer end 25 shorter leg, said attachment being of substan
of the bolts I4 and I5 as shown.
The manner in which my adjustable ladder
can be made to accommodate itself readily to
different ground surfaces will be apparent from
Figs. 1, 2 and 5. In Fig. 1 the ladder is assumed
to be standing on `a level surface.’ The bottom
of the adjustable attachment I6 and the bottom
of the leg Il are accordingly arranged so as to
be in the same horizontal plane.
This of course
is the normal position of the adjustable attach
ment I6. In Fig. 2 the left hand side of the
ladder is required to be supported at a lower level
than the right hand side. To accommodate the
ladder to such uneven ground surface the clamp
tially the same cross section as said shorter leg,
a recess in the inside face of said attachment ad
jacent the outside face of said shorter leg, a sec
ond plate secured in said recess, said second plate
being longer than said ñrst mentioned plate and
said ñrst mentioned plate and second plate hav
ing cooperating engaging teeth on their opposed
faces, the depth of said recess being equal to the
combined thicknesses of said plates when said
vplates have their teeth inengagement, whereby
the opposed faces >of said attachment and said
shorter leg Wil1 contact each other above and be
low said recess when the teeth of said plates are
in engagement, a pair of clamping bolts extend
ing nuts 2| are loosened and the adjustable at 40 ing outwardly through the longitudinal center
tachment is lowered the desired distance, Where
line of said shorter leg and located above and
upon the clamping nuts 2| are tightened. This
below said ñrst mentioned plate, a pair of slots
extending> along the longitudinal center line of
adjustment is very easily and quickly made. In
Fig. 5, on the other hand, the right hand side of
said attachment above and below said recess, said
the ladder is required to be supported Vat a lower 45 bolts extending through said slots respectively,
and clamping nuts on the outer ends of said
level than the left hand side. The same simple,
quick adjustment is all that is required to ac
commodate the ladder to this particular uneven
ground surface._ In this case the adjustable at
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