Foldable inclined multi-section ramp actuation system

A foldable, articulated inclined ramp or stair assembly actuation system is shown and described. The assembly comprises at least three elements connected by hinges to each other and foldable on each other under the control of a series of pulleys interconnected by a single drive cable. A method of operating the arrangement is described whereby an orderly folding sequence is automatically maintained by the actuating means. The assembly is suitable for installation within an aircraft and may be power driven to extend and retract through a loading door, thus obviating the need for any ground equipment for the purpose.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an actuation system for multi-section devices, 
such as self-contained ramps and ladders mounted within transport vehicles 
for providing loading and unloading of cargo and passengers when the 
vehicle is stationary. 
2. Description of the Prior Art 
It has long been known to provide a multi-section ramp or stairway assembly 
which can be wholly contained within a transportation vessel or vehicle 
such as an airplane or a ship. U.S. Pat. No. 2,933,149 of Lee, 
representative of known prior art in this field, discloses a 
self-contained stair unit for extension from an aircraft by means of a 
series of linkages and levers. Such units as are known typically involve 
rotation in both the clockwise and counterclockwise direction about 
various axes of rotation along the extended, articulated stair assembly. 
It has also been known before to actuate the extension and retraction of 
the stairway assembly by the movement of a cable attached to pulleys which 
are capable of rotating the articulated assembly as desired by means of 
various mechanical linkages. A cable assembly actuating arrangement 
representative of the prior art is seen in U.S. Pat. No. 2,531,263 of Fink 
et al. Another representative patent showing such cable actuation of the 
rotation of the various sections of the stairway assembly about respective 
axes of rotation can be seen in U.S. Pat. No. 3,083,784 of Uriah. In such 
arrangements, it is characteristic that the assembly will fold or unfold 
in zigzag fashion by rotating about adjacent axes of rotation in opposite 
directions. 
SUMMARY OF THE INVENTION 
The present invention contemplates the provision of a multi-section stair 
or ramp assembly comprising a plurality of individual sections, each 
adjacent pair of which is joined together by a hinge arrangement to permit 
folding of the two sections together. Each individual section has an 
offset hinge bracket of sufficient dimension to permit the adjacent 
outboard section and the other, more outboard sections folded thereagainst 
to be folded up against the individual section about the hinge axis. A 
multiple pulley and cable arrangement is connected to a drive mechanism 
such as a motor to fold and unfold the ramp. It is to be understood herein 
that the term "ramp" is used to mean a sloping way such as a sloping floor 
leading from one level to another or a stairway or ladder for entering or 
leaving the main doors of aircraft or similar transportation vehicles. A 
pair of pulleys is mounted at each hinge axis between adjacent sections 
and also at the pivot axis of suspension of the ramp in a vehicle. The 
pulleys are free to rotate upon their axes and are offset from each other 
to avoid interference when the ramp sections are folded together. A cable 
having its opposite ends wound about and attached to a drum mounted on the 
power drive shaft is wound about all of the pulleys such that a moment is 
developed on each section equal to the pulley radius times the force in 
the cable. As tension is placed on one end of the cable by the drive shaft 
to effect folding of the ramp, force is developed at the farthest extended 
section which causes it to rotate about the next upstream pulley and hinge 
axis. Unfolding is effected by developing tension in the other cable which 
applies a force at the outer inboard folded section, causing it and all 
other folded sections to rotate about its inboard hinge axis. For ramps 
not cantilevered from one end, each hinge mechanism is provided with a 
mechanical toggle and toggle release member so that the hinge mechanism is 
locked open against folding except when that particular hinge mechanism is 
to be used as the pivot axis in the folding sequence. At least one of the 
outer sections is provided with a pivotable support member coupled by a 
linkage mechanism to the next inboard section and driven between retracted 
and extended positions thereby as the outer section folds and unfolds 
relative to the next inboard section. 
Particular arrangements of the multi-section actuation system in accordance 
with the present invention have particular applicability in recently 
developed aircraft which are designed to operate independently of ground 
equipment and therefore require self-contained stairways or ramps. This is 
particularly true for aircraft that are relatively high off the ground and 
require more than one or two folding sections. By virtue of the folding 
and unfolding design of the present invention, the actuating system may be 
made lighter and more efficient than previously known devices. In the 
presented arrangement, only one section is moved against resisting forces 
at any given time. Thus the sizes of the various pulleys may be tailored 
to generate an efficient overall load stroke curve within the limits of 
the available actuating power source capability. System simplicity and 
reliability are enhanced by the use of the closed loop cable system to 
drive the ramp, a considerable improvement over previously known ramp 
devices which require multiple hydraulic cylinders and related equipment 
to transfer hydraulic fluid pressure across folding joints. 
In accordance with an aspect of the present invention, the respective ramp 
sections fold in a manner such that the first section which is folded, 
ends up in the center of the folded stack. Ramp actuating force is 
provided through a closed loop cable system powered by a single actuator. 
At each ramp hinge pivot, there are two freely rotating pulleys with a 
360.degree. cable wrap. The wrap on the two pulleys is in opposite 
directions to provide extending and retracting forces. During retraction, 
the pulleys which are upstream of the folding ramp section will idle with 
cable motion. As the sections are folded and stopped by the section ahead 
of it, the cable motion and pulley motion at that hinge are also stopped. 
This action provides an automatic sequencing of ramp sections by the 
increase in hinge moment required to lift a section out of sequence. With 
proper sizing of the respective pulleys in order to maintain an efficient 
load stroke curve, it requires twice the power to lift two sections out of 
sequence as it does to lift both in proper sequence. To extend the ramp, 
the sections are trapped, one inside the other, thus providing correct 
sequencing in the extension direction. 
One preferred embodiment of the invention establishes the sections, when 
extended, as a unitary, colinear inclined ramp (the conventional ramp) 
suitable for installation in aircraft such as are provided with hospital 
beds and medical attendants for use in aero-medical evacuation work, the 
transporting of hospital patients, and the like. Such a configuration is 
suitable for on-and-off loading of patients in wheelchairs, on hospital 
gurneys, on stretchers, and the like. 
An alternative arrangement in accordance with the present invention 
provides an inclined ramp with stair-step configured sections for the 
traversal of crew and/or passengers to and from the aircraft. In both 
embodiments, the ramp is supported at one end on the aircraft. The 
actuation system can be applied to any multiple element extendible unit 
for use in similar fashion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As seen in the accompanying drawings, particularly FIG. 1, a ramp 10 is 
shown comprising a plurality of individual sections. A first section 12 is 
seen connected by a hinge mechanism 14 to a floor or platform 16 of the 
transportation vehicle, such as an airplane 18. The first ramp section 12 
is mounted for rotation about axis 20 which constitutes part of the hinge 
14. Pulley 22 rotates about axis 20 in the hinge 14 arrangement. 
As seen in the view of FIG. 1, the ramp 10 also comprises a second section 
24 which is connected to the first ramp 12 by virtue of hinge arrangement 
26. Second ramp section 24 is mounted for rotation about an axis 28. 
Pulley 30 also rotates about axis 28. The second ramp section 24 is 
connected in the hinge arrangement 26 so that second ramp section 24 is 
pivotably connected to move about axis 28 of rotation free of the pulley 
30. 
The multi-section ramp 10 is shown in the preferred embodiment having a 
third section 34. Third ramp section 34 is connected by hinge arrangement 
36 to second ramp section 24. Third ramp section 34 rotates about axis 40. 
Pulley 38 also is capable of rotating about axis 40 relative to second 
ramp section 24. Second ramp section 24 is attached to third ramp section 
24 pivotably within the hinge 36, so that when the third ramp section 34 
and pulley 38 are being rotated about axis 40, second ramp section 24 may 
remain stationary. 
Additionally, further ramp sections may be made part of the ramp assembly 
10 depending on the distance which is to be covered by the sloping ramp 
10. In the particular embodiment shown in FIGS. 1-3 of the drawings, a 
fourth ramp section 44 is shown. Fourth ramp section 44 rotates about axis 
48. Both the pulley 46 and the fourth ramp section 44 are adapted to be 
rotated independently about the axis 48 of hinge mechanism 50. The third 
ramp section 34 is connected to the fourth ramp section 44 through the 
hinge arrangement 50, so that fourth ramp section 44 and pulley 46 may be 
rotated about axis 48 independently of third ramp section 34. 
Additionally, fifth ramp section and further ramp sections may be added to 
the ramp assembly 10 as desired. In the view of the embodiment seen in 
FIG. 1 in the drawings, only four ramp sections are seen. A pulley 
attached to a fifth ramp section could be provided, if desired, so as to 
connect the movement of such a fifth ramp section about an axis of 
rotation with the automatic movement of the first, second, third and 
fourth ramp sections by common cable means. 
Cable 64 is adjustably affixed at one end to an adjusting screw 54 which 
itself is attached to the fourth section 44. Thus, both ends of the cable 
64 can be stretched or loosened by working of the screw 54. In such a 
manner, the final adjustment of the tension within the cable can be made 
and can be altered as seen fit by maintenance crew. 
The cable is wound about pulley 46, thence wound about pulley 38, thence 
wound about pulley 30, thence wound about pulley 22, thence wound about 
drum or axle 66. All windings of cable 64 are 360.degree. wraps. Between 
adjustment screw 54 and drum 66, the windings are in the same direction so 
that this portion of cable 64 constitutes the upper strand as seen in the 
drawings. After being wound about drum 66, the cable is wound again around 
pulley 22 in a 360.degree. wrap, but in the opposite direction of the 
first wrap or wind. Then the cable 64 is wound around pulleys 30, 38, and 
46 in succession, each in the opposite direction to the first wrap so that 
the return portion of cable 64 consitutes the lower strand. The cable 64 
is then connected to adjustment screw 54 on fourth ramp section 44. 
As can be seen in the accompanying drawings, the cable 64 as it leads from 
the fourth ramp section 44 inboard is wound around the respective pulleys 
in opposite rotational direction from the other portion of the cable 64 
leading toward the fourth ramp section 44. Thus, upon rotation of the drum 
66, the pulleys 22, 30, 28, 46 are rotated uniformly in one rotational 
direction identical to the rotational direction of the drum 66. It may be 
observed that in the embodiment of FIG. 1 of the drawings, the drum 66 and 
the axes 20, 28, 40, 48 of rotation are all parallel. The movement of the 
respective pulleys 22, 30, 38, 46 is always in the direction identical 
with each other by virtue of the connection of the cable 64 and its 
threading about the various pulleys and the drum 66. Drum 66 can be 
rotated by a motor 67 as shown, or by manual rotation as desired. 
Mechanical advantage can be provided a manual operator by gearing linkage 
in the usual manner. 
It is not necessary that the pulleys around which the cable 64 is wound 
between the various sections necessarily be a single pulley. It is 
contemplated, for example, that two pulleys may be provided between each 
of the sections, one each for the upper strand and the lower strand wraps. 
As may be seen better in FIG. 2A of the drawings, hinge mechanism 26 may 
have pulleys 70 and 71 mounted to rotate about rotation axis 28. The upper 
strand may be wound around one pulley 70 in a 360.degree. wrap as shown. 
The lower strand of cable 64 will be wrapped around pulley 71, likewise in 
a 360.degree. wrap. The pulleys 70 and 71 may have axially mounted between 
them a bushing, not shown, to prevent the abutting of the two pulleys. 
Similar to the pulleys 30, 38, 46 and 22 about their corresponding axes of 
rotation, pulleys 70 and 71 are mounted to be free idling pulleys on the 
axis 28. 
Third section 34 is provided with a ramp support leg 74, as best seen in 
FIGS. 4 and 5 of the accompanying drawings. FIG. 4 is a partial view of 
FIG. 1 taken from the opposite side of the ramp assembly 10 as seen in 
FIGS. 1 and 2, showing ramp section 34 and portions of ramp sections 24 
and 44. Ramp support leg 74 is fixed to axle 75 which is rotatingly 
mounted within section 34. The axle 75 is parallel to the axes 48 and 40. 
A crank or lever 26 is affixed at one end of the axle 75. The crank 76 is 
connected by a tie rod 77 to a fixed point 78 on the second section 24. 
The fixed point 78 must be positioned longitudinally along the ramp 
section 24 offset from the axis 40. 
FIG. 5 is a partial view of the ramp assembly 10 showing ramp section 34 
partially rotated about the axis 40. The operation of the ramp support leg 
in cooperation with the rest of the elements of the ramp assembly 10 will 
be explained in greater detail below. 
It is contemplated that the various sections are locked into their extended 
positions so that in the extended mode, the sections will not rotate about 
their corresponding axes of rotation. This further aspect may be 
appreciated with reference to FIGS. 6 and 7 of the accompanying drawings. 
Again, like reference numerals are used in FIGS. 6 and 7 to denote similar 
or identical elements as found in FIGS. 1-4 of the drawings, for 
simplicity of understanding of the invention. 
The first ramp section 12 is seen in FIG. 6 in the extended position 
abutting the extended second ramp section 24. A hinge arrangement 26 is 
shown having rotation axis 28 between the first ramp section 12 and second 
ramp section 24. The third ramp section 34 is shown in the process of 
being rotated about its rotation axis 40. A first link 81 is shown 
pivotably attached at point 80 to first section 12. A second link 82 is 
shown pivotably attached at point 83 to second section 24. The first bar 
81 and the second bar 82 are pivotably attached to each other at an apex 
84 in a toggle joint arrangement such that the apex 84 will go over center 
and create a latch between sections 12 and 24. It is to be noted that the 
first link 81 is relatively longer than the second link 82. 
The toggle link mechanism is placed on the lower side of the sections 12 
and 24 so that when the second section 24 is rotated into the extended 
position, it comes to rest in abutment with section 12, and the apex 84 
comes to a rest slightly higher than the line connecting the pivotal point 
80 and pivotal point 83. To provide assurance that the apex 84 will go 
over center and come to a rest at a point somewhat higher than this line, 
a spring 85 is connected between the arm 82 and the first section 12. 
Tension is thus provided tending to rotate arm 82 in the counterclockwise 
direction about pivotal point 83, as seen in FIGS. 6 and 7 of the 
accompanying drawings. The second section 24 is then locked from any 
rotation either in the clockwise or counterclockwise directions until the 
apex 84 of the toggle joint is dislodged from its resting position. 
An arm 86 is provided on the third section 34. When the third section 34 is 
rotated as indicated by the arrow in FIG. 6 of the accompanying drawing, 
into a position adjacent the second section 24, the arm 86 will engage the 
bumper or link 82 so as to dislodge the apex 84 against the tension of the 
spring 85. The toggle joint will then be forced into an unlocked position 
as shown in FIG. 7. As the drum 66 is rotated in a manner so as to fold 
the multi-sections into adjacent relationship with each other, second 
section 24 may be rotated without hindrance from the unlocked toggle joint 
between the first section 12 and the second section 24. The details of the 
rotation of the various sections into and away from each other will be 
explained in greater detail below. In the manner as explained, however, it 
can be seen that rotation of second section 24 about rotation axis 28 
cannot commence until the third section 34 comes to a rest adjacent second 
section 24, and the arm 86 unlocks the toggle joint as seen in FIG. 7. 
In such a manner, the folding and the unfolding of the ramp sections is 
accomplished in a sequential order. In a similar manner, an identical 
toggle joint may be arranged between second section 24 and third section 
34 in the hinge arrangement 36. A lever arm 87 is fixed on fourth section 
44, so as to engage the apex, not shown, of the similar toggle joint in 
hinge arrangement 36. 
In operation, the various sections of the multi-section ramp assembly 10 
can be folded by rotating the ramp sections about various axes of rotation 
until the entire ramp assembly is folded with the various ramp sections 
adjacent each other. Rotation of the folded assembly is continued about 
axis 20 into or within the aircraft 18 as seen in FIG. 3 of the 
accompanying drawings. Positions of the various sections of the ramp 
assembly 10 during operation can be better seen in FIG. 2 of the 
accompanying drawings. 
Upon rotation of drum 66, as explained above, each of the pulleys 22, 30, 
28, 46 is rotated in the same rotational direction about its corresponding 
axis of rotation, by virtue of the movement of cable 64. If, as seen in 
the view of FIG. 1 of the accompanying drawings, drum 66 is rotated in the 
clockwise direction, the pulleys 22, 30, 38, 46 are all driven in the 
clockwise direction about their corresponding axes of rotation. The cable 
64, upon the clockwise rotation of drum 66, increases in tension along its 
upper length, pulling against the anchor member 55 and applying a 
clockwise moment to the ramp section 44 about the pulley 46. The opposing 
torques at the various hinge axes, resulting from the respective 
cantilever loads of the various sections, are such that the farthest 
outboard section is lifted and rotated about its adjacent hinge axis. 
Also, for ramps not wholly supported by the upper end, the remaining 
inboard sections 34 and 24 are prevented from rotating about their 
corresponding rotation axes 40 and 28 by virtue of the toggle joint hinge 
locking mechanism described above in regard to FIGS. 6 and 7. The result 
is the rotation of the fourth ramp assembly 44 in a clockwise direction 
about axis 48 of rotation. The clockwise rotational movement of the fourth 
ramp section 44 continues until it is folded against the third ramp 
section 34, at which point arm 87 unlocks the toggle joint arrangement of 
hinge mechanism 36 (FIG. 6), permitting rotation of the next section. 
If the drum 66 continues to be rotated in the clockwise direction, the 
upper strand of cable 64 between pulley 38 and pulley 46 can be seen to be 
increasing in tension or tending to be shortened in length, while 
complementally the lower strand of cable 64 between the same two pulleys 
38, 46 can be seen to be decreasing in tension and tending to be 
increasing in length. Such a result has the effect of urging both ramp 
sections 34 and 44 in the clockwise direction about axis 40 of rotation, 
as illustrated in FIG. 2 of the drawings. The third ramp section 34 and 
folded fourth ramp section 44 are moved in the clockwise direction about 
rotation axis 40 until both ramp sections 34, 44 come into an adjacent 
relationship with second ramp section 24. Axis 40 is offset from the ramp 
sections slightly so that the folded fourth ramp section 44 and third ramp 
section 34, when folded into adjacent relationship with the second ramp 
section 24, will be substantially parallel to the second ramp section 24 
and thus occupy the minimum amount of volume or space. 
When the folded third section 34 and fourth section 44 are rotated about 
axis 40, tie rod 77, fixed to stationary second section 24, forces the 
crank or lever 76 to remain in a defined position relative to the axis 40. 
Consequently, in the counterclockwise rotation of the folded third and 
fourth sections 34, 44 as seen in FIGS. 4 and 5, third section 34 will 
appear to rotate relative to axle 75. Ramp support leg 74 then comes into 
adjacent relationship with third section 34 as indicated by the arrow in 
FIG. 5. Third section 34 may be grooved or recessed so that when leg 74 
comes into adjacent relationship with the third section 34, the leg 74 may 
fit within the recess or groove. Rotation of third section 34 in the 
opposite or clockwise direction as seen in FIGS. 4 and 5, will cause the 
leg 74 to extend relative to the third section 34, providing that the 
second section 24 remains stationary. The second section will remain 
stationary by virtue of the lock mechanism of hinge arrangement 26, as 
explained above. 
Again and similar to the operations of the more extended ramp section 34, 
44, the continued rotation of drum 66 increases tension and tends to 
shorten the length of the upper strand of cable 64 between the pulley 30 
and pulley 38, while reducing tension and tending to extend the length of 
the lower strand of cable 64 between the same two pulleys 30, 38. The 
result of this force on the upper strand of cable 64 between the pulleys 
30, 38 is to urge the folded second, third and fourth sections 24, 34, 44 
of the ramp assembly in a clockwise rotation about axis 28, referring now 
to FIGS. 1-3. Again, the folded second, third and fourth sections 24, 34, 
44 of the ramp assembly continue in this clockwise rotation until the 
three folded sections become folded adjacent to first ramp section 12. The 
axis 28 of rotation is also offset slightly from the ramp sections 12, 24, 
so that when the second ramp section 24, third ramp section 34 and fourth 
ramp section 44, all folded adjacent each other, are rotated about axis 28 
of rotation into adjacent relationship with the first ramp section 12, the 
second ramp section 24, third ramp section 34 and fourth ramp section 44 
all will be substantially parallel to the first ramp section 12. 
The continued rotation of drum 66 tends to place a tension on the upper 
strand of cable 64 between the pulley 22 and pulley 30, and to create a 
reduced tension in the lower strand of cable 64 between the same pulleys 
22 and 26. The folded first, second, third and fourth sections 12, 24, 34, 
44 are urged thus in a clockwise rotation about axis 20. The rotation of 
the folded sections of the ramp assembly continues in the clockwise 
direction about axis 20 until the entire assembly thus folded has been 
rotated to within the confines of the vehicle, such as aircraft 18 as seen 
in FIG. 3 of the drawings. The rotation should continue until such time as 
further rotation is prevented by some suitable stop, not shown. 
In extending the ramp sections from their folded position as seen in FIG. 3 
of the drawings, back to the extended position as seen in FIG. 1 of the 
drawings, the drum 66 is merely rotated in the opposite or 
counterclockwise direction as seen in FIGS. 1-3 of the drawings. Thus, the 
rotation of drum 66 in the counterclockwise direction will cause an 
increased tension in the lower strand of cable 64 between the pulleys 22 
and 30, while simultaneously reducing tension and tending to increase the 
length of the upper strand of cable 64 between the same pulleys 22 and 30. 
The result of the increased tension in the lower strand between the 
pulleys 22 and 30 causes a counterclockwise rotation of the entire folded 
assembly about axis 20. The counterclockwise rotation of the entire folded 
assembly continues until the first ramp section 12 meets with some stop, 
such as the platform 16 of the aircraft 18 as seen in FIGS. 1-3 of the 
accompanying drawings. 
If the drum 66 is continued to be rotated in the counterclockwise 
direction, the tension in the lower strand of the cable 64 between the 
pulleys 30 and 38 is increased substantially while the tension in the 
upper strand of the cable 64 between the same pulleys 30, 38 is reduced. 
The lower strand tends to be shortened in length while the upper strand 
tends to be extended in length, thus causing a rotation of the remaining 
folded second, third and fourth sections 24, 34, 44 about axis 28 of 
rotation in the counterclockwise direction. The counterclockwise 
directional rotation of the second section 24 and of the folded sections 
34, 44 folded thereon, continues until the second section is stopped by 
its abutment with the first section 12 at the now adjoining edge 25 of the 
second section 24 and the edge 13 of first section 12. 
The continued rotation of drum 66 in the counterclockwise direction will 
then substantially increase the tension in the lower strands of cable 64 
between the pulleys 38 and 46, while substantially reducing the tension in 
the upper strand of cable 64 between the same pulleys 38, 46. Again, the 
lower strand of the cable 64 tends to be shortened in length, while the 
upper strand of the same cable between the same pulleys tends to be 
extended in length. In such a manner, the third section 34 and the 
remaining, more remote sections, such as fourth section 44 folded onto 
third section 34, are rotated about axis 40 in the counterclockwise 
direction. The counterclockwise movement of third section 34 and more 
remote sections folded thereon continues until prevented by the abutment 
of edge 35 of third section 34 with edge 27 of second section 24. 
The continued rotation of drum 66 in the counterclockwise direction, as now 
may be appreciated, then results in an increased tension in the lower 
strand of cable 64 between the pulley 46 and the point at which the cable 
is connected with fourth section 44 at adjustable set screw 54. At the 
same time, a reduced tension is found in the upper strand of cable 64 
between the same pulley 46 and the same point. The result of these 
tensions within the cable 64 causes the fourth section 44 to rotate in a 
counterclockwise direction about axis 48 of rotation. The counterclockwise 
movement of fourth section 44 continues until the edge 45 of fourth 
section 44 abuts with the edge 37 of third section 34. Further 
counterclockwise rotation of the fourth section 44 is then prevented. 
While the fourth section 44 is being rotated about axis 48, the first, 
second and third sections 12, 24, 34 remain in a stationary position. 
While the folded third and fourth sections are rotated about axis 40 of 
rotation, the first and second sections 12, 24 remain stationary. While 
the second, third and fourth sections 24, 34, 44, folded into adjacent 
relationship with each other, are rotated jointly about axis 28, the first 
section 12 remains stationary. 
In such a manner the folded ramp assembly as seen in FIG. 3 of the drawings 
is extended so as to provide a ramp between platform 16 of the aircraft 18 
and the lower ground level 60. The extending of the ramp assembly 10 from 
the fully folded position to the fully extended position is done by 
rotating the various sections in identical directions about their 
parallel, corresponding axes of rotations. Further, there is only one axis 
at any one time about which rotation of the ramp assembly is accomplished. 
Substantial reduction in the amount of power required to drive the drum 66 
is realized. Similarly, when the extended ramp assembly as seen in FIG. 1 
of the drawings is folded into a compact folded assembly from the extended 
positions, the rotation of each of the respective sections into adjacent 
folded relationship with the other sections, is accomplished by rotation 
of the sections in an identical direction of rotation about each 
corresponding axis of rotation. Further, there is only rotation about one 
axis of rotation at any one time. Thus, efficiencies in power required to 
drive drum 66 are realized. 
An alternative embodiment of the invention can be seen in the illustration 
of FIG. 8 of the accompanying drawings. Specifically, a first section 90 
is seen having stair steps or rungs 92 positioned thereon. Second section 
100 abuts at its edge 102 with edge 91 of first section 90. Second section 
100 is rotatingly connected to first section 90 by virtue of hinge 
arrangement 96, of which axis of rotation 98 is a part. Third section 110 
in the extended position, as seen in FIG. 8, has its edge 112 abutting 
edge 106 of the second section 100. Third section 110 is rotatingly 
connected to second section 100 by hinge arrangement 116, so that third 
section 110 can rotate about an axis 118 of hinge arrangement 116 in the 
counterclockwise direction as seen in the view of FIG. 8, until third 
section 110 can be folded against second section 100. 
Thereafter second and third sections 100, 110, folded together against each 
other, can be rotated about axis 98 until they come into parallel adjacent 
relationship with first section 90. The axis 98 of rotation is offset 
somewhat from the first section 90 and second section 100 so that the 
sections 110 and 100 folded together can be placed in substantially 
parallel, adjacent relationship when rotated into adjacent relationship 
with first section 90. First section 90 is affixed to lever 120 which is 
rotatably connected to the platform 122 of the airplane 124. Lever 120 can 
rotate about axis 126. When lever 120 is so rotated in the 
counterclockwise direction as seen in the view of FIG. 8, the folded first 
section 90, second section 100 and third section 110 can be folded 
counterclockwise into the aircraft 124, as seen in phantom in the view of 
FIG. 8. 
Cable 130 is shown beginning at a point 132 where it is attached to third 
section 110. Cable 130 is then wound in a 360.degree. wrap around pulley 
114 which rotates about axis 118. Cable 130 is then wound in a 360.degree. 
wrap around pulley 104 which rotates about axis 102. Cable 130 is then 
wound around pulley 94 which rotates about axis 93. The cable is then 
wound back around pulleys 104 and 114, thence is fixed to the third 
section 110 at the point 132. At each pulley, the return portion of cable 
130 is wound in a 360.degree. wrap in the opposite direction of the first 
wrap similar to the arrangement of cable 64 in the first embodiment 
described. Pulley 94 can be rotated by a crank 95 connected directly to 
the pulley 94, or may be rotated by a rotary power source such as an 
electric motor (not shown). 
In operation, the extended ramp assembly as seen in FIG. 8 of the drawings 
can have its several sections folded onto each other, and the entire 
folded assembly rotated to within the aircraft 124, as seen in the phantom 
drawing of FIG. 8. The folding operation is accomplished in a manner 
substantially similar to the folding of the ramp assembly 10 as seen in 
the embodiment described in FIGS. 1-7 of the accompanying drawings. Thus, 
pulley 94 can be rotated in the counterclockwise direction, in the view of 
FIG. 8. Such rotation causes an increased tension in the upper or 
right-hand strand of cable 130 between the point 132 and the pulley 114. A 
lessened tension results in the lower or left-hand strand between the same 
pulley 114 and point 132. The resulting moment causes a counterclockwise 
(as viewed in FIG. 8) rotation of third section 110 until it comes into 
adjacent, parallel relationship with second section 100. The 
counterclockwise rotation of these folded outboard sections continues 
until they come into adjacent, substantially parallel relationship with 
first section 90. Because of the substantial offset of the axis of 
rotation 98, it will be possible for the second section 100 and the third 
section 110 to come into substantially parallel relationship when they are 
brought into adjacent relationship with first section 90. The entire 
folded assembly may then be placed within the aircraft 124 simply by 
rotating the folded sections 90, 100, 110 about the axis 126 in a 
counterclockwise manner until the entire folded assembly rests against a 
stop or against the platform 122 within the aircraft 124. 
To put the folded ramp assembly into an extended position, it is only 
necessary to rotate the folded assembly about axis 126 in a clockwise 
direction. Ultimately, the bracket 120 will come to rest against the 
platform 122. At this time, pulley 94 can be rotated in the clockwise 
direction to develop an increased tension in the lower or left-hand strand 
of cable 130 and a decreased tension in the upper or right-hand strand of 
cable 130 as seen in the view of FIG. 8. This causes a clockwise rotation 
of folded second section 100 and third section 110 about the axis 98. 
Clockwise rotation of second section 100 and third section 110 continues 
until edge 102 of second section 100 comes to rest in adjoining or 
abutting relationship with edge 91 of first section 90. Further rotation 
of second section 100 is then blocked until the continued rotation of 
pulley 94 causes an increased tension in the lower or left-hand strand of 
cable 130 between the pulleys 104 and 114, while decreasing the tension in 
the upper or right-hand strand of cable 130 between the same pulleys 104, 
114. Such tensional forces, as may be now appreciated, cause a clockwise 
rotation of third section 110 while second section 100 remains stationary. 
Section 110 continues in a clockwise rotation until its edge 112 comes 
into abutting relationship with edge 106 of second section 100, at which 
time third section 110 cannot rotate further in the clockwise direction. 
At this time, rotation of pulley 94 can be stopped, and the ramp assembly 
can be used to convey passengers from a ground level to the platform 122 
within the aircraft 124. 
Again as in the preferred embodiment described earlier in this 
specification, it can be seen that rotation is produced about only one 
axis of rotation at any one time. In such a manner, the torque required to 
drive pulley 94 in either direction can be substantially reduced, compared 
to the torque that might be required to rotate all of the sections 
simultaneously about the respective axes of rotation. Furthermore, the 
ramp assembly can be folded neatly into adjacent adjoining sections and 
easily placed within the aircraft 124. 
If desired, the ramp sections 90, 100, 110 may be joined to each other at 
respective abutting edges by virtue of a toggle joint arrangement as is 
described above, reference being had to FIGS. 6 and 7 of the drawings. In 
such a manner, the extended sections may be locked into a non-rotating 
position relative to the next inboard section until the toggle joint is 
placed in an unlocked position by virtue of abutting arms, such as arms 
86, 87 as seen in FIGS. 5 and 6 above. 
It will be noted that the hinge brackets connecting the respective ramp 
sections to their corresponding hinge axes are of different dimensions and 
configurations in order to accommodate the different spacings between 
commonly hinged ramp sections in the folded position. Thus hinge brackets 
21, 23 are of different lengths and shapes from brackets 31, 33 which in 
turn are different from brackets 41, 43. The effect of this structural 
feature may be best seen in FIG. 3. Also, as is apparent in FIG. 3, the 
respective bracket pairs and the corresponding pulleys are laterally 
offset from hinge to hinge by virtue of the slight overall taper of the 
ramp 10 (see FIG. 1) thus facilitating the stowage in minimal space in the 
folded position. 
Although there have been described above specific arrangements of foldable 
inclined multi-section ramp systems in accordance with the invention for 
the purpose of illustrating the manner in which the invention may be used 
to advantage, it will be appreciated that the invention is not limited 
thereto. Accordingly, any and all modifications, variations or equivalent 
arrangements which may occur to those skilled in the art should be 
considered to be within the scope of the invention as defined in the 
appended claims.