Improvements in Stair Lifts.
Year: 1899

page_text: Date of Application, 6th Dec., 1899-Accepted, 17th Mar., 1900
Improvements in Stair Lifts.
I, JAMES MAPES DODGE, of McKean Avenue and Clapier Street, Germantown,
in the City of Philadelphia, State of Pennsylvania, United States of America,
Engineer, 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:-
My invention relates to certain improvements in endless belt conveyors whereby
they are so guided as to form the treads and risers of a moving stairway, or more
properly a stair lift.
The object of my invention is to so construct the belt that it can be flexed not
only at the pivot points to form the treads and risers but also between these points
for the purpose which I will hereafter describe, with reference to the accompany-
ing drawings, of which
Figure 1 is a sectional elevation of my improved stair lift;
Figure 2 is a diagrammatic perspective view;
Figure 3 is an enlarged sectional view showing a portion of one step and
adjoining risers;
Figure 4 is a plan view of Figure 3:
upper
Figure 5 is a view showing the belt passing around the
Figure 6 is a plan view of a portion of the upper roller:
roller;
Figure is an enlarged sectional view on the line 7-7, Figure 1;
. Figures 8, 9 and 10 are perspective views of different forms of links; and
Figures 11 and 12 are perspective views of the form of links used at the front
edge of a tread.
A is an endless belt made up in the present instance of a series of links a
hinged together by pins passing through lugs or depending portions of the
links, so as to form a continuous surface. These links are capable of moving on
their pivots to a certain extent for the purpose hereinafter fully described.
Arranged at given distances apart are pivots B.B. carrying at their outer ends
rollers or wheels which are adapted to fixed guideways. The pivots B. B. are
secured to the links of the belt in the present instance by rings encircling
the pivots and having perforated projections through which the pivot pins b pass.
The pivots B. B. are each preferably secured to two pivot pins as shown in
Figure 3.
The structure, therefore, consists of an endless belt having pivots B at given
distances apart, the pivots in the present instance extending beyond the belt,
and the belt is so constructed as to be capable of being flexed between the said
pivots.
D. D. are guideways for the pivots B, B': these two guideways merge into
each other at either end of the stair lift and connect with a return guide D³,
as clearly shown in Figure 1.
E is a sprocket wheel situated at the upper end of the stair lift, this wheel

page_text: is small and engages with the pivot pins b of each link; and has a gap into
which the pivot rods B, B, enter as shown in Figure 5. The sprocket wheel E
is driven in any suitable manner.
At the lower end of the stair lift I preferably provide a drum F which is an
idler and is simply provided for the purpose of carrying the belt from the return
guideway D to the elevating guideways. Recesses are formed in this drum
for the reception of the pivots B. B. and are preferably provided with recesses
for the reception of the pivot pins of the links.
It will be noticed that the upper floor or landing I is arranged slightly below
the upper surface of the belt as it passes around the wheel E so that it is impos-
sible for any thing to catch between the belt and the floor. The lower floor I'
is slightly below the level of the belt but may be on the same plane.
The guideway D' has a channel into which extends the ends of the pivots B
which may be provided with rollers, by this arrangement the pivots B will pass
through the guideway D while the pivots B₁ will pass through the guideway D'
'so as to form the steps.
The deflection of the belt takes place at a point at or near the lower floor and
the pivots B. B¹. are so arranged that alternate pivots travel in the different
guideways D. D¹. so that treads and risers are formed. For instance, the rollers
at the outer edge of the treads travel in the guideway D while the rollers at
the inner edge of the treads travel in the guideway D'. thus it will be seen that
as the belt passes from the idler drum F first a tread is formed, then a riser,
then a tread and so on, and a person can step onto the stair lift during the form-
ing of the treads, the risers always being at an angle will prevent a person step-
ping on that portion of the belt.
It will be noticed that the riser sections do not assume a vertical position as
in an ordinary stairway, but preferably remain in an inclined position, as shown
in Figure 1. By this arrangement the freads can be made narrow, but the space
between the treads is increased so as to give sufficient room between one passenger
.and another.
When the tread upon which the passenger is carried reaches the top of the
stair lift the passenger can readily step onto the landing and the belt, which is
flexible between the pivots, will disappear around the sprocket wheel E and
return, thus taking up very little room at the upper landing.
I preferably form the belt of a series of metallic links of the forms shown in
Figures 8, 9, 10, 11 and 12, and I may make these either of forged or malleable
castings.
Each link consists of a body portion and depending lugs a' at each side, the
lugs being of the form shown, so that the lugs on each link will lap those on adja-
cent links. The pivot pins 7 pass through openings in these lugs to connect the
links together.
Each link has a tongue 2 which underlaps the body portion of the adjoin-
ing link so that the belt will have a continuous surface. The tongues are so
proportioned that they will underlap the depending link when the belt turns
around the sprocket wheel E.
The form of link shown in Figure 8 is that used for the body of the belt
between the pivots B and B. while the form of links shown in Figures 9 and 10
are used at the junction of the inner end of the tread and the lower portion of
the riser, as indicated at 1 and 2. Figure 3. the edges of the link 2 are cut away
and the surface of the link 1 is bevelled as indicated at in Figure 3 so that
when the riser is forming the link 2 can pass over the link 1.
The links shown in Figures 11 and 12 are indicated in Figure 3 by the
numerals 3 and 4 they being arranged at the junction of the riser and the outer
edge of the tread, and the tongue 2 of the link 3 extends the full width of the
tread and the depending portions or lugs a¹ of the link 4 are undercut at at to
receive this tongue, so that there will be no opening at the outer edge of the

page_text: tread and the tongue is of Sum
leng in to autop the aujo
turning around the sprocket wheel E.
It will be understood that other forms of links may be used without departing
from the main feature of my invention.
Thus it will be seen that the endless belt is made up of a number of links coupled
together by the pins b, the link at the joints of the treads with the risers being
so formed that there will be as little opening as possible at these points.
It will be understood that in some instances, instead of making the belt of
pivoted links as shown, it may be made of any flexible material such as leather,
and so formed that the treads will support the load, but I prefer to use the
links, as I can form them in such a manner that they will readily yield in one
direction but be perfectly rigid and support the load in the opposite, direction,
and furthermore the construction is comparatively cheap and substantial.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In a stair lift, the combination of a series of treads and risers hinged to-
gether, each tread and riser being flexible, substantially as hereinbefore described.
2. In a stair lift, the combination of a series of treads and risers hinged together,
each tread and riser being flexible, and a head wheel around which the treads and
riders are flexed in passing from one run to the other substantially as herein-
before described.
3. In a stair lift, the combination of a series of treads and risers, each tread and
riser being flexible, a small wheel at one end of the stair lift around which both
the treads and risers are flexed, and a fixed platform in close proximity to the
treads and risers as they pass around the wheel, substantially as hereinbefore
described.
4. In a stair lift, the combination of an endless belt made up of a series of
flexible treads and risers pivoted together, guides for the pivots, a drum at the
lower end of the stairway around which the treads and risers are flexed, a platform
in close proximity to the drum and the surface of the belt, a small wheel at the head
of the stair lift around which the treads, and risers are flexed, and a fixed plat-
form in close proximity to the belt at the point where it passes around the head
wheel, substantially as hereinhefore described.
5. In a stair lift, the combination of an endless band having pivots at given
distances apart to form treads and risers, the said band being flexible between the
pivots only in a vertical direction, whereby the band can be flexed around guide
wheels, substantially as hereinbefore described.
6. The combination in a stair lift, of an endless flexible band, having pivots at
given distances apart, two guideways, alternate pivots adapted to one guideway
and the other pivots adapted to the other guideway, the said guideways merging
into each other at each end of the stairway and communicating with a return
guideway, substantially as hereinbefore described.
7. In a stair lift, the combination of an endless band made up of series of short
enchained links pivoted at given distances apart, the hands being vertically
flexible between the pivots, with guides whereby treads and risers are formed by
guiding alternate pivots out of line, substantially as herein before described.
8. The combination in a stair lift, of guideways D. D1, D2, the guideways D DI
merging into each other at the upper and lower portions of the stairway and
communicating with the return guideway D, an idler at the lower portion of the
stair lift. a sprocket wheel at the upper portion of the stair lift, and a flexible
endless helt adapted to the rollers and adapted to be flexed by the guideways sub-
stantially as hereinbefore descrihed.
9. In a stair lift. the combination of an endless band having pivots at given
distançes apart, said band being flexible between the pivots, guides for the

page_text: pivots and a sprocket wheel around which the band passes a gap in the sprocket
wheel and pivot bars entering the gap in the sprocket wheel, substantially as
hereinbefore described.
10. The combination in a stair lift, of an endless flexible band having pivots at
given distances apart two guideways, alternate pivots adapted to one guideway
and the other pivots adapted to the other guideway, the said guideways merging
into each other at each end of the stairway and communicating with the return
guideway, a channel in one guideway into which one set of pivots extend, sub-
stantially as and for the purpose herein before described.
11. In a stair lift, the combination of guides, an endless belt having pivots at
given distances apart and adapted to the guides, the said guides being so formed
that on the carrying run the endless belt will be so arranged that the belt will
be formed into treads and risers and the risers will be inclined throughout the
carrying run of the stair lift, whereby the horizontal distance between the steps
will be increased substantially as and for the purpose hereinbefore described.
12. In a stair lift, the combination of guides, a series of treads and risers hinged
together, forming an endless belt, means for driving the said belt, each tread and
riser being made up of a series of links hinged together so that the said steps and
risers will be flexible, the upper surface of each link being curved, a head wheel
around which the treads and risers are flexed, the curved surface of each link
being such that a cylindrical surface will be formed as the endless belt passes
around the head wheel, and a platform in close proximity to the belt, substan-
tially as herein before described.
Dated this fith day of December 1899
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.