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A WHEELED TROLLEY FRY.
This invention relates to trolleys of the type used to
transport goods, examples are supermarket trolleys and
luggage trolleys as used in airports.
With the advent of multi-story shopping centers and airports
escalators have been introduced with a view to facilitating
the transport of persons from floor to floor. Ramps have
been installed in many multi-story buildings to enable
persons to move trolleys from floor to floor. So as to
facilitate the movement of trolleys up the ramps the
inclines have been carefully designed but even so there is a
reluctance by persons to push a loaded trolley up a ramp.
Because of this it has become common for persons to limit
their purchases in shopping centers to floors where they can
have immediate access to car parking facilities and by so
doing avoid the above problem.
To counter this practice multi-story car parks have been
built alongside multi-story shopping centers so persons so
inclined can park adjacent the floor where they will be
making their purchases and transporting them in a shopping
trolley. This however leaves the older and less well
designed shopping centers with the problem of how to easily
transport trolleys from floor to floor. In many shopping
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centers person conveying escalators are installed but trolleys
have not hitherto been designed for use with such escalators, This
invention provides improvements in trolleys which will allow them
to travel safely with the user on the escalator from floor to floor.
The present invention provides a wheeled trolley frame
for use on an escalator, four ground engaging wheels comprising a
pair of wheels adjacent each of two ends of the frame, said wheel
pairs being spaced to thereby prevent the wheel pairs from not
only sitting upon a single tread of a step of an escalator but
also on the treads of two consecutive steps of an escalator,
positioning means on the frame adjacent the first pair of wheels,
an abutment face on said positioning means extending beyond the
first pair of wheels adapted to engage the riser of a formed
escalator step preceding the escalator step over which the first
pair of wheels is positioned, a first escalator tread engaging
member fixed to the frame located between the pairs of wheels and
between the wheels of the first pair of wheels and vertically
spaced above a ground plane on which all of the wheels would
normally rest, a pair of second escalator tread engaging means fixed
to the frame between the pairs of wheels and respectively adjacent
the wheels of the second pair of wheels and vertically spaced above
the ground plane, the first and second escalator tread engaging
members providing a three point support for the frame when mounted
on a formed escalator, said first and second escalator
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tread engaging members being respectively spaced from the abutment
face of the positioning means by predetermined distances, whereby
when the frame is on a formed escalator with the abutment face
engaging a step riser preceding a first escalator tread the first
tread engaging member bears on the first escalator tread and the
first pair of wheels are positioned above and spaced from the
first escalator tread and the second tread engaging members bear
on the following second escalator tread and the second pair of
wheels overlie the following third escalator tread and are
spaced therefrom.
Several presently preferred embodiments of the invention
will now be described with reference to the accompanying drawings
in which:-
Fig. 1 is schematic elevation of a shopping trolley made according to one embodiment of the invention when entered
onto an escalator as the steps are about to form,
Fig. 2 is a view similar to Fig. 1 after the escalator
steps
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have formed.
Fugue is a view similar to Foggily of a second embodiment of
the invention,
Fugue is a view similar to Yoga after the escalator steps
have formed,
Fugue is a view similar to Foggily of a third embodiment of
the invention,
Fugue is a view similar to Fugue after the escalator steps
have formed, and
Fugue is a perspective elevation of the trolley of Fugue
showing details of the construction.
In the drawings there is shown a shopping trolley by way of
example but the invention is applicable to other forms of
trolleys such as low level platform luggage trolleys as used
in airports. For this reason the invention can be
considered as being directed to a wheeled trolley frame on
which goods supporting attachments, such as a basket, can be
secured. As illustrated the trolley frame l of Foggily has a
front pair of wheels 2 and a rear pair of wheels 3. On the
I frame l adjacent the rear wheels 3 there are support members
4, one adjacent each rear wheel 3 and they are elevated a
small distance above a common plane on which all four wheels
would normally rest if the frame was not on the escalator.
The escalator section shown includes five treads To, To, To,
To, and To separated by risers Al, R2 and R3 (see Fugue).
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The tread widths are the same and for the purposes of later
explanation will be considered as being equal to I. It will
be noted from Foxily and 5 that the pitch of the wheel
pairs is such that when the wheels 2 on the tread To abut
the riser Al the rear wheels 3 are on tread To with the
support member above the tread To.
From Fugue it will be seen that as the escalator steps fully
form by the treads To to To rising relative to the tread To
the tread To comes into contact with the support members 4
of Foggily and and the wheels 3 are raised clear of the tread
To. The trolley frame will travel in this manner safely
supported on its two front wheels 2 and the two supports 4
until the escalator steps begin to uniform at the end of the
escalator travel at which time the reverse procedure will
occur. More specifically, the treads To to To will rise
relative to the tread To and the wheels 3 will be engaged to
cause the supports 4 to disengage with the tread To.
Figs. 3 and 4 illustrate a similar set of circumstances
showing a trolley frame l on which there is a single or a
double support means 5. The support means 5 preferable
includes a forwardly projecting travel limiting stop 6 to
engage against the riser Al. The pitch between the wheels 2
and 3 in this embodiment has been shortened only because of
the shape of the trolley frame. If desired the trolley
frame can be modified to allow the wheels 3 to rest upon the
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tread To rather than the tread To. This arrangement however
could result in a severe slope for the trolley frame with
the center of gravity of a load in the basket disposed too
far to the rear and for the reason it is proposed to have
the arrangement as illustrated.
Fox and 6 show a trolley frame having the features of
Foxily and 3 and is the preferred arrangement in that the
trolley frame is supported off all wheels 2 and 3. As will
be seen from Fox and 6 the trolley frame is supported on
both the support means 4 and 5 on adjacent escalator treads
To and To.
The presently preferred trolley frame and basket is shown in
the perspective view of Fugue where a wire basket 7 with
associated handle 8 is secured to the frame l. The support
member 5 is shown fixed to a curved bar providing the
forward movement limiting means 6 but it is to be understood
that the bar 6 is optional as the wheels 2 can be used in
place of the bar 6. It will be appreciated however that for
practical reasons the bar 6 is preferred. The wheels 2 and
3 are shown as catering wheels which is the preferred form
to facilitate the wheeling of the trolley.
The member 5 can be pivotal connected to the bar 6 to
allow minor adjustments of angle to occur to facilitate the
largest possible surface contact of the foot 5 with the
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escalator tread with weaken it is engaged. Pivoting also
allows the foot 5 to swing up to pass over obstructions such
as speed humps on roadways and parking areas.
The support means 4 are elongated members fixed to the
frame l and the supports 4 and 5 are preferably covered with
rubber or like high-grip material.
To provide workable embodiments of the invention certain
operating and constructional criteria must be observed. For
example it is a fundamental requirement that in loading the
trolley frame onto an escalator that the frame be advanced
until the wheels 2, in the Foxily and 2 embodiment, or the
travel limiting stop 6, in the other embodiments, be engaged
against a riser R. This positions the other components
such as the wheels 3 and the support means 4 and/or 5 in the
correct positions for the successful support of the trolley
frame on the escalator. For example the supports 4 and/or 5
must lie intermediate the wheel pairs 2 and 3.
By way of explanation of a preferred arrangement reference
will be made now to Fugue where a datum line L is provided
and the positioning of the components are referred thereto.
The discussion relates to a trolley frame when positioned on
a fully formed escalator. Distance D and Do from the end of
the member 6 where it engages the riser Al and the contact
point of 5 with the tread To and the contact point of 4 with
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To should not result in the members 5 and 4 resting on the
rear edges of the steps where the risers and the treads
intersect at the points R2,T2 and R3,T3, otherwise an
unstable situation could result. The distance Do should not
be such as to result in the wheel 3 bearing on the tread
rear edge R3,T3 for fear that the angle of the trolley and
the weight thereof would overcome the frictional grip
between the member 5 and the tread To and cause the wheels 3
to drop off the edge R3,T3 towards the tread To creating a
space between the riser Al and the member 6. From a
theoretical standpoint however this would be acceptable
provided that the rearward movement did not result in the
members S and 4 moving rearwardly beyond the edges R2,T2 and
R3,T3 as an unstable condition could then occur, but they
could rest on those edges.
In view of the foregoing the theoretical conditions to be
met are as follows. For all forms of the invention the
support means for the trolley frame on the escalator issuer
intermediate the wheel pairs. For the Fugue and Fugue
embodiments the distance D is less than X-a (i.e. D<X-a)
where X is the width in the operating direction of the
escalator steps and O'er and r is the radius of the wheels
3, where naturally X is greater than or. The distance Do
is greater than no and is less than (n+l)X-a,
(i.e. nX<Dl<(n+l)X-a) where n is a whole number equal to or
greater than l. The distance Do is greater than (n+l)X-a,
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(i.e. D>(n+l)x-a!.
The foregoing parameters if killed with will ensure that
should the trolley move backwardly because of engagement of
wheels 3 with the edge R3,T3 the member 4 will seat on a
tread other than that above which the wheels 3 will be
positioned and that the member 5 will remain on the tread
over which the wheel 2 is positioned. To practice all of
the foregoing would be taken into account when the distances
D to Do were being designed and a margin for safety above
the pure theoretical considerations would be allowed. For
example the distances D and Do could be reduced by an amount
sufficient to ensure the majority of the seating surfaces of
the members 5 and 4 would be resting on the treads To and To
for the condition where the wheels 3 were peripherally
abutting the riser R3.
As for the height Hi of the contact point of 5 above a
reference plane on which all four wheels 2 and 3 will rest
this is related to the escalator operating angle. Assuming
the escalator angle is B degrees then, referring to Fugue,
if the contact point of member 5 lay on or above a line
tangent to the wheel 2 at an angle B to the horizontal (the
assumed reference plane) then when the trolley frame was on
the fully formed escalator of Fugue or 6 the wheel 2 and the
member 5 would be both resting on tread To which is not the
required arrangement where the member 5 engages and the
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wheel 2 does not engage. In view of this the contact point
of 5 must be no lower than the reference plane RIP of Figs. 3
and 5, otherwise it would prevent the trolley frame from
moving on its wheels, and no higher than the tangent to the
wheels 2 at an angle to the reference plane equal to the
escalator operating angle of B. From Fugue it will be seen
that the maximum height is therefore d tan B degrees.
As for the height Ho of the contact point of 4 above the
reference plane RIP this must be less than the height Y of
110 the riser R3, otherwise the wheels 3 will not be raised from
the tread To and naturally the contact point of 4 cannot be
lower than the reference plane RIP.
With the embodiment of Foxily and 2 the requirements for Do,
Do and Ho would apply as they do to the Fox and 6
arrangement and D would not apply. With the Fox and 4
embodiment the requirement for D and Hi would apply but Do
would not apply and Do would be such as to ensure that the
the wheels 3 are on a tread other than that on which wheels
2 are supported.
