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Патент USA US3100557

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Aug. 13, 1963
H. HOPFELD
3,100,552
CONVERTIBLE LADDER
Filed Feb. 21, 1961
2 Sheets-Sheet 1
Iz'g_ 3.
INVENTOR.
HE/W? Y HOPFELD
ATTORNEY
Aug. 13, 1963
H. HOPFELD
3,100,552
CONVERTIBLE LADDER
'
Filed Feb. 21, 1961
'
2 Sheets-Sheet 2
INVENTOR.
HENRY HOPFELD
BY /
_
ATTORNEY
United States Patent 0
1
Patented Aug. 13, 1963
2
2,100,552
CQNVERTEBLE LADDER
_
Henry Hopteld, 732 A St, San Rafael, Calif.
Filed Feb. 21, 1961, her. No. 9d,6%
2 Claims. ((11. 1$2—22)
grid-i552!
1
‘
3 on the top of each rail 1 of the lower ladder A. Each
bracket 3 includes a base plate 4 provided with suitable
holes 6 to accommodate securing elements such as rivets
‘55 or the like to mount it on the inner face of the rail 1.
The base plate 4 projects beyond an edge of the adjacent
rail 1 and its projecting end is formed into a retainer
guide 7 which conforms substantially to the contour of
the rail 1 of the upper ladder B. In the present form the
This invention relates to a convertibleladder.
The primary feature of this invention is that a ladder
is provided which can be converted quickly into various
retainer guide 7 is generally U-shaped, the open end of
types as needed, for instance, into a step ladder or used 10 the U-shape being offset inwardly of the adjacent rail of
as two straight ladders, or as an extension ladder; this
the lower ladder A. The lower edge of the closed end
convertibility is accomplished by the coaction of a joint
or joining bracket and guides coacting with suitable abut
of the U-shaped retainer guide or socket 7 is provided
with an outwardly ?aring lip 8, away from the adjacent
ments on the respective ladders and other devices as
rail of the lower ladder, generally at an angle correspond
shown to quickly convert the two ladders in the various 15 ing to the ‘angle of incline of the adjacent rail 1 of the
arrangements as needed.
upper ladder B in the stepladder position.
I. am aware that some changes may be made in the
At the lower inner corner of the base plate 4, is a
general arrangements and combinations of the several
rest ?ange 9 at an ‘angle generally parallel with the angle
of the lip 8 so that the face of the rest ?ange 9 is spaced
devices vand parts, as well as in the details of the con
struction thereof without departing from the scope of the
present invention as set ‘forth in the following speci?ca
tion, and ‘as de?ned in the following claims; hence I do
not limit my invention to the exact arrangements and
combinations of the said device and parts as described in
the said speci?cation, nor do I con?ne myself to the exact
details of the construction of the said parts as illustrated
from the lip 8 at such a distance that the rail 1 of the
upper ladder B in the stepladder position engages the in
side of the parallel lip 8 and rests on the rest flange 9
as shown in FIG. 2.
The rest ?ange 4 has a base 1%?
which partly overlaps the base plate 4 and is suitably
attached to the rail 1 and to the base plate 4. On the top
edge of the base plate 4 is a top plate 11 corresponding
in the accompanying drawings.
With the foregoing and other objects in view, which
to the contour of the top of the adjacent rail 1 of the
lower ladder A. This top plate 11 has suitable holes 12
will be made manifest in the following detailed descrip
tion, reference is had to the accompanying drawings for
the illustrative embodiment of the invention, wherein:
FIG. 1 is a perspective view partly in’ section showing
the top of the adjacent rail 1.
to accommodate screws 13 to secure the top plate 11 onto
Near the top of each rail of the upper ladder B are
provided a pair of dogs 14 and 15 olfset longitudinally
the two ladders combined into a stepladderm
FIG. 2 is ‘a fragmental view of the top portion of the
on opposite edges 16 of the rail 1 of the upper ladder B
the respective ladders.
abutment ends 17 of the respective dogs 14 and 15 is
FIG. 3 is a fragmental sectional view of the top por—
tion of the ladders showing the manner of disengagement
substantially the same ‘as the distance between the upper
PEG. 4 is a view showing the ladders converted into
In this illustration the top of the ladder B is covered
by a generally U-shaped recessed cover plate 19 suitably
secured in place.
so that the upper dog 14 is nearer to the upper end of the
stepladd‘er with the coacting bracket and abutment on 35 rail 1 than the lower dog 15'. The spacing between the
edge 18 of the rest ?ange 9 and the lower edge of the
of the ladders from the stepladder position into straight 40 lip 8 so as to abut against said edges in the stepladder'
ladders.
position of the ladders A and B as shown in FIG. 2.
on extension ladders.
FIG. 5 is a fragmental edge View of the coacting brack
ets and 'abutments on the tops of the ladders.
The hook means for supporting the upper ladder B as
FIG. 6 is a fragmental sectional view the section being 45 an extension, in the present illustration, are a pair of
taken approximately on the lines 6-6 of the FIG. 2.
hooks 21, one of which is suitably secured to the inner
FIG. 7 is a detail perspective view of the top bracket
‘face of each rail 1 of the upper ladder B at the lowest
viewing from the side of the guide.
rung 2 of said upper ladder B.
'
FIG. 8 is another perspective view of the top bracket
In operation the two ladders A and B can be quickly
viewing from the base plate, the rail being shown in 50 assembled to form ‘a stepladder by inserting the top ends
broken lines.
of the rails 1 of the upper ladder B into the guide or
In carrying out my invention 1 make use of ‘a pair of
socket 7 in a position substantially as shown in FIG. 3 so
straight ladders A and B at the upper ends of which are
that the upper dog 14 passes through the guide 7 and
coacting means C adapted to hold the two ladders to
the lower dog 15 is in registry with the lower end of the
gether at a suitable angle for forming a usual stepladder. 55 lip ‘8. The dogs 14 and 15 are of such height that total
The coacting means C are releasable by bringing the
width of each rail ‘1 and the height of either dog is less
step ladders A and B toward a parallel position and the
than the space between the lower edge of the rest ?ange
coacting elements on the top of the ladder A are adapted
9 and the lip 8 so that the rail with the dogs can be passed
to function .as guides and retainers for the upper ladder
therethrough where the upper rail 1 is nearly parallel
B when the two stepla-dders are used as extension lad 60 with the lower ladder A. Then the ladders are tilted to
ders. The connecting means C is also adapted for per
about the incline shown in FIG. 2, in which position the
mitting quick disengagement of the tops of the ladders
upper edge 16 of each rail 1 of the upper ladder B abuts
for separation into two straight ladders. Suitable means
against the lip 8 and the lower edge of the same rail 1
are provided for resting the lower end of the ladder B
rests upon the rest ?ange 9. In this position the upper
on the rungs of the ladder A when the same are used as 65 dog 14 bears against the upper edge 18 of the rest ?ange
an extension ladder as shown in FIG. 4.
9 and the lower dog 15 bears against the lower edge of the
Each straight ladder A and B has a pair of parallel rails
lip 8. As weight is placed upon the stepladder from either
1 connected by the usual rungs 2. The straight ladder
side, it will tend to push the ladders apart and the more
B, used as an extension, is of such width that it slidably
weight hears upon the step ladder the ?rmer will be the
?ts between the rails 1 of the lower ladder A.
locking engagement between the edges of the nails 1 of
The coacting connecting means C includes a bracket
the upper ladder and the lip 8 and the rest ?ange 9 re
3,100,552
ll
vspectively. and the ?rmer will 'be the engagement by the
respective dogs 14 and 15.
contour ‘of the adjacent rail of the upper ladder so as
For separating the ladders, the same are moved to
gether to a less acute angle so that the rails of the upper
ladder B assume substantially the position shown in FIG.
to embrace the latter in said extension-ladder attitude,
1(lz) a rest ?ange extended from said base plate spaced
from said guide atan incline corresponding to the
relative incline of said upper ladder in said step
3, then the ladder A may be moved upwardly relatively
ladder attitude and at such a distance from the lower
to the ladder B and as it is further moved toward the
edge of said retainer guide that the upper edge of the
panallel position, it will permit the upper dog 14 to pass
through the space between the lip 8 and the rest ?ange
9‘, thus severing the connecting means between the ladders 10
and resulting in two straight ladders.
said retainer guide when the lower edge of said rail
rail of said upper ladder engages the lower edge of
of said upper ladder rests on said rest ?ange,
_ (i) a ?rst abutment projecting from the lower edge of
the rail of said upper ladder,
In order to use the same combination as an extension
ladder, the upper and lower ladder A and B are placed in
the position shown in FIG. 3, but in this instance the
(j) and a second abutment projecting from the upper '
upper ladder B is pushed upwardly and in'the position
shown in FIG. 3, the lower dog 15 will pass through the
(k) said abutments being spaced longitudinally of said
guide 7 upwardly and as the upper ladder B assumes the
distance between the upper edge of said rest ?ange
edge of the rail of said upper ladder,
' rail of said upper ladder at a distance equal to the
posiiton parallel and overlapping with respect to the lower
and the lower edge of said retainer guide so as' to
ladderA, the rails 1 of the upper ladder B nest in the
respective channel guides 7 as shown in FIG. 4, and are 20
allowed to be slid parallel into desired extended position
in which position the respective hooks 21 can be placed
over the adjacent rung 2 of the lower ladder A, as shown
in FIG. 4, to hold the two ladders in extended position so
?x said upper rail against longitudinal movement
relatively to said retainer guide in said step-ladder
that the upper ladder is supported by the hooks and by 25
the guides or sockets 7.
The adaptability of two ladders into various types of
combinations ‘without the use of any other attachments is
of great advantage, it in effect provides four ladders in
one with quick adjustments, ‘assemblies and attachments
position and the rails of said upper ladder ride on the
to accomplish the desired result.
I claim:
rungs of the lower ladder,
(m) and releasable means to hold said ladders to
gether in selected extended relation.
1. In a convertible ladder structure
(a) a lower individual ladder,
(b) an upper individual ladder,
(c) the rails of the upper ladder sl-idably ?tting be
tween and along ‘the respective rails of the lower
2. A convertible ladder structure as de?ne-d in claim 1,
35 and
ladder,
(d) and separate connecting means on said individual
ladders ‘to connect said ladders selectively in step 40
ladder attitude and extension-ladder attitude com
prising
(e) a bracket on the top’ of each rail of said lower
ladder, each bracket including
(1‘) a base plate secured to a face of the adjacent rail,
(g) an end of said bracket projecting toward the upper
ladder and beyond ‘the edge of the adjacent rail and
being for-med into a retainer guide conforming to the
attitude,
(I) the thickness of each abutment together with the
width of its rail being less than the distance between
the lower edge of said inclined rest ?ange and the
lower edge of said guide to that the upper end por
tion of said rail of said upper ladder is movable be
tween said guide and said ?ange in either direction.
respectively for extension and separation of said lad
ders when said ladders are in substantially parallel
(11) an outwardly ?aring lip on the lower edge of said
guide parallel with said inclined rest ?ange for en
gaging the upper edge of said rail of said upper lat‘
der in said guide in step-ladder attitude.
References Cited in the ?le of this patent
UNITED STATES PATENTS
675,744
766,246
Lewis ________________ __ June 4, 1901
Hartzler ; ____________ __ Aug. 2, 1904
- 1,579,701
Givens _______________ __ Apr. 6, 1926
1,996,133
~ 2,133,003
White ________________ __ Apr. 2, 1935
Webster _____________ _; Oct. 11, 1938
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