Folding pushchair

A folding pushchair has a chassis provided on each side with two chassis struts (6, 7) carrying wheels (8). The struts are pivotally connected together, and swing out of a folded position, in which they lie side by side, into a position of use, in which they are secured by means of a fastening device (14). This device has to swing upwards to release the struts but a seat, and hence the weight of a child in the pushchair bears down on the device (14), thereby avoiding accidental folding in use. The folding pushchair is designed so that it can be self supporting in a stable upright position when in its folded condition.

FIG. 7 shows the frame for a pushchair as depicted in FIGS. 1 or 2 but in a 
further intermediate position during folding of the pushchair, said 
position coming closer to a folded position of the pushchair. 
FIG. 8 shows the frame for a pushchair as depicted in FIGS. 1, 3 and 7 in 
the folded position. 
The pushchair shown in FIG. 1 comprises a chassis 1, a push handle 2, a 
foot part 3, and a seat part 4, which is merely indicated in FIG. 4 in the 
form of a board. A back part 5 of the pushchair can be seen in FIG. 3. All 
parts of the pushchair which are made of textile material, such as seat 
coverings, seat side walls and a hood, are omitted from the drawings for 
the sake of clarity. 
The chassis 1 consists essentially of two chassis struts 6 and 7 on each 
side. At the end of each chassis strut a wheel 8 is mounted. Double wheel 
sets may also be provided. The other ends of the chassis struts 6 and 7 
are in each case articulated side by side on a connecting plate 9, so that 
they are pivotable relative to each other. They are pivotable in the same 
plane, so that in a folded position (not shown) of the pushchair they lie 
with their mutually facing sides directly against one another. On the 
connecting plate 9 is additionally supported a safety yoke 10, which in 
plan view is substantially U-shaped and the free ends of which are 
articulated on the push handle 2 (see FIG. 3, in which, for the sake of 
clarity, parts of the chassis struts 6 and 7, the connecting plate 9 and 
parts of the safety yoke 10 have been omitted on the side of the pushchair 
which lies at the rear from the viewer's viewpoint). 
The push handle 2 is movably joined by a first intermediate link 11 to the 
part of the chassis strut 6 which lies near the wheel, and by a second 
intermediate link 12 to the second chassis strut 7. The latter is the 
chassis strut situated at the front in the direction of travel. The second 
intermediate link 12 acts on the push handle 2 above the first 
intermediate link 11. FIG. 2 shows the position of use of the pushchair. 
In this position the intermediate links 11 and 12 hold the push handle 2 
in such a manner that it is supported by its free bottom end on the 
chassis strut 6. The point of support has for the sake of clarity been 
shifted somewhat downwards in the accompanying diagrammatical 
illustrations. It is expediently situated approximately at seat height, so 
that the textile coverings of the seat and of the back region, integrated 
into the push handle (FIG. 3), adjoin one another. 
A fastening device 13 fastens the chassis struts 6 and 7 in their open 
angular position relative to one another when the pushchair is in the 
position of use shown in FIG. 2. The fastening device 13 is shown on a 
larger scale in FIG. 4. On both sides it has a rigid arm 14. The two arms 
14 are joined by crossbars 15 to form a frame. At one end of the arms 14 
the ends of a crossbar 15a project beyond the frame on both sides. It thus 
engages in a pivot bearing 16 on the first chassis strut 6. At the end 
remote from the bearing, each arm 14 has a nose 17 which is open at the 
bottom and which forms the latching means for the fastened position of the 
fastening device. In this position (FIG. 2) it engages over a pin 18. In 
FIG. 4 the arms 14 are extended beyond the crossbar 15a to form a U-shaped 
yoke 19 integral with it, the cross web 19a of which forms a pedal for 
operating the fastening device. It is provided with a pedal covering 20. 
In FIGS. 1, 2 and 6 the fact that, as already mentioned, the push handle 2 
is set back relative to the chassis strut 6 has the effect that it cannot 
be seen that the pedal 19a can be reached with the foot from the rear of 
the pushchair. In FIG. 3, however, the positions of the push handle 2 and 
of the pedal 19a can be seen correctly. 
In its position of use shown in FIG. 2 the fastening device 13 engages by 
its nose 17 over the pin 18. A tension spring 21, which is fastened at one 
end to the arm 14 and at the other end to the chassis strut 6, urges the 
nose 17 into this latching position. The seat 4, indicated in FIG. 4, is 
fastened by means of mountings 22 on the crossbar 15a and is supported on 
the arm 14 and the other crossbars 15. It transmits to the arms 14 the 
weight of a child sitting in the pushchair. For the purpose of folding the 
pushchair, the operator presses down the pedal 19a with the foot. The arms 
14 are thus swivelled upwards and the nose 17 is disengaged. The seat 
surface 4 participates in the upward swivelling movement. With the 
simultaneous forward movement of the push handle 2, the chassis struts 6 
and 7 swivel towards one another until they reach their final position, 
one against the other. An intermediate stage in this movement, directly 
after the unlocking, is shown in FIG. 1. The nose 17 has already lifted 
off the pin 18, and the angle between the chassis struts has already been 
somewhat reduced. The push handle 2 is situated with its bottom end 
already some distance from the strut 6 and can be swivelled further 
forwards. The tension spring 21 has no further effect. 
If the pedal 19a is operated while the seat surface is still carrying a 
weight, particularly the weight of a child, the weight counteracts the 
swivelling movement of the arm 14. The operator is thereby prevented from 
continuing the swivelling movement by force, or at least is warned against 
doing so. 
In addition to the details of the pushchair which have already been 
described in connection with FIGS. 1 to 4, FIG. 3 also shows the 
construction of the back part 5. It is not joined to the seat part, so 
that its position does not hinder the cooperation of the seat part and the 
fastening device. The seat part 5 comprises a U-shaped back bow 23, which 
is mounted on the push handle 2 in the region of the free ends of the 
latter. The mounting is effected by means of a toothed segment 24, which 
is here indicated on one side only end and in which the back yoke can be 
fastened and locked in various positions by means of a crossbar 25. The 
position assumed is maintained by means of springs, which are not shown 
here. For unlocking purposes the crossbar 25 is joined to a likewise 
U-shaped pull means 26, the upper yoke 26a of which can be gripped 
together with the U-web of the back yoke 23. If, when so gripped, the pull 
means is pulled upwards to the U-web of the back yoke 23, the latter is 
unlocked in the region of the toothed segment 24 and can be swivelled to 
another position. 
In FIG. 3 it is also indicated how an end wall yoke 27 adjoining the cross 
web of the back yoke 23 can be swivelled forwards at an angle to the yoke 
23. This position of the end wall yoke is in itself assumed when the back 
yoke 23 is swivelled into a lying position of the pushchair, that is to 
say to form an extension of the seat surface, and with the aid of the end 
wall yoke 27 and the (indicated) textile side parts 28 a closed 
trough-like head part can be formed in the pushchair. 
A construction of pushchair which differs from that described above, in 
respect of the construction of its fastening device 13', is shown in FIGS. 
5 and 6. In these Figures identical components are given the same 
reference numerals, while corresponding parts are given the same reference 
numerals with the addition of a dash. The fastening device 13' has on each 
side, instead of a rigid arm, two lever arms 14a and 14b articulated to 
one another. The arms 14a are mounted by means of a crossbar 15a, which 
connects them together, on the swivel bearing 16 of the chassis struts 6, 
as in the example shown in FIGS. 1 to 4. The lever arms 14b are mounted 
for swivelling by means of bearing bores 29 on articulation points 30 of 
the chassis struts 7. The articulation 31 between the arms 14a and 14b 
connects the free end of the arm 14a to a region of the arm 14b remote 
from both ends. The arms 14b are in each case situated outside the arms 
14a. The extension 32 of the arm 14b freely projecting beyond the 
articulation 31 follows a curved path. A cross strut 33 connects the ends 
of the extensions 32 of the arms on the two sides. 
FIGS. 5 shows the fastening device 13' in its dead centre position, which 
corresponds to the fastening position: the arms 14b assuming in relation 
to the arms 14a a position in which the cross strut 33 rests from above on 
the arms 14a. A relative movement between the arms 14a and 14b is 
therefore possible only in the form of a downward movement of the arms 14a 
in the region of the crossbar 15a, that is to say by means of the pedal 
19a, or in the form of a downward movement of the arms 14b in the region 
of their bearing bores 29, whereby the cross strut 33 is moved upwards. 
This movement is the unlocking movement, the initial stage of which is 
shown in FIG. 6. It can be made through the operation of the pedal 19a 
without noteworthy resistance only when the seat board 4, which is to be 
imagined to be above the crossbar 15a and the cross strut 33, is not under 
load, that is to say when there is no child sitting in the pushchair. The 
loading of the seat surface 4 forces the cross strut 33 downwards and thus 
forces the fastening device 13' into the dead centre position described. 
Additional securing by means of a spring is therefore unnecessary. 
With particular reference to FIGS. 7 and 8 of the drawings, FIG. 7 shows an 
intermediate state of the frame for the inventiive pushchair, in which the 
frame is in a more collapsed position with respect to the position shown 
in FIG. 1. The length of the first and second intermediate links 11, 12 as 
well as the length of the safety yoke 10 are selected to enable the pivot 
point of the push handle, at which it is pivotably connected to the first 
intermediate llink, to travel along an annular path during collapse of the 
pushchair frame. This leads to the result that the push handle 2 and the 
first chassis strut 6 approach the state during folding of the pushchair 
frame, in which they are, in general, in parallel. In the folded position 
of the pushchair frame, which can be seen in FIG. 8, the push handle 2 and 
the first chassis strut 6 are in a position in which they lie side by 
side, and are in general in parallel. The distance between the wheel axis 
and the pivotal connection point of the first chassis strut 6 has been 
selected so that it is longer than the distance between the wheel axis and 
said pivotal connection point 9 of the second chassis strut. In the folded 
position shown in FIG. 8, in which the first and second chassis struts 6, 
7 are also arranged side by side, the wheels coupled to the first chassis 
struts are in a lower position than the respective wheels coupled to the 
second chassis struts. Therefore, when said chassis struts 6, 7 as well as 
the push handle 2 are arranged vertically in the folded position of the 
pushchair frame, said frame can be supported so that it rests only upon 
the rear wheels coupled to the first chassis struts 6, and not upon the 
front wheels coupled to the second chassis struts 7. 
The length of the first intermediate link 11 plus the length of the push 
handle 2 between the pivot point at which it is connected to the first 
intermediate link 11 and its lower or bottom end portion is, in general, 
equal to the distance between the pivot point at which the first 
intermediate link 11 is connected to the first chassis strut 6 and the 
lowermost point of the wheel 8 coupled to said strut 6 when the first 
chassis strut is in an upright position. This leads to the result that in 
the folded position of the pushchair frame, it can be stood up in an 
upright position, in which it rests only upon the lowermost portions of 
the respective wheels 8 coupled to the first chassis struts 6 and upon the 
lowermost end portions of the push handle 2. The lowermost end portion of 
the push handle 2 is preferably provided with bumper means arranged, for 
example, within the interior of the lowermost end portions of the push 
handle 2. 
In the folded down position shown in FIG. 8, it is possible to put the 
pushchair down in a safe manner where it will stand upright in a 
self-supporting condition. The pushchair or stroller will thus be 
positioned in a convenient form where it will not readily fall over or 
roll away. In this folded position the pushchair is compact, is stable, 
and has the handle portion of the push handle presented in a convenient 
position for handling the pushchair, whether the folded pushchair is to be 
lifted, or displaced along the rear wheels 8, or merely held after folding 
or prior to and during unfolding. 
The invention is not restricted to the illustrated examples. An essential 
consideration is the simple folding and the fastening device which 
prevents unintentional folding of the pushchair while a child is sitting 
in it. Variable arrangements include the cross connections between the 
arms of the fastening device, the shape, size and design of a foot pedal, 
the construction of the safety yoke and its connection to the various 
components, and also the construction of individual articulations.