Note: Descriptions are shown in the official language in which they were submitted.
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
Passenger Loading Bridge for Small Aircraft and Method of ~ligr ing Same
Field of the Invention
The invention relates generally to a passenger loading bridge, in particular an
extensible loading bridge having two extensible sections for positioning the loading
s bridge and for fine alignment with the entry door.
Background of the Invention
Passenger loading bridges have gained world-wide acceptance for the safety and
convenience they afford passengers. Most major air terminals are provided with gates,
gangways or passenger loading bridges which extend from the second level of the
0 terminal to a parked aircraft. Frequently, these bridges are relatively immobile since
aircraft can park close to the terminal and be moved away by tugs or tractors.
Commonly, passenger loading bridges have been directed to standard size
passenger and cargo aircraft and consequently, have been relatively large in size and
height. They have not generally been practicable for use with small aircraft such as, those
5 employed in feeder lines to smaller or outlying communities. Accordingly, passengers
typically have had to walk from the terminal over airport tarmac and thence up a stairway
in order to enter a small aircraft. This exposes passengers to inclement weather and
hazards such as propellers, cables, and fuelling hoses. It is not desirable to subject
passengers to inclement weather or to potentially dangerous ramp conditions. Also,
20 aircraft operations are significantly slowed by allowing passengers onto the tarmac. For
safety reasons, aircraft and equipment remain stationary while passengers are on the
tarmac. Security is a concern because passengers can board incorrect aircraft or tamper
with other craft. In order to increase security, it is a common practice to board only one
aircraft from the tarmac at any time. With passenger loading bridges in place, luggage is
25 loaded, aircraft tests are executed, other aircraft are taxied, and so on while passengers
board the aircraft. Other aircraft are capable of being boarded simultaneously when
sufficient gates exist. It is therefore desirable to provide a passenger loading bridge for
use at these smaller air terminals to enhance the safety and comfort of passengers.
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
Commonly, smaller air termin~l~ are only ground level structures at which aircraft
park a fixed distance from the terminal building. There frequently are no tugs available.
This fixed distance is required to enable the aircraft to "power out" or move away from
the building under its own power without ~l~m:~gin~ the building with a jet or propeller
5 blast, or a physical collision between the aircraft and the terminal. This distance is
greatest with a Boeing 727-200 aircraft, which is the largest aircraft normally serving
these smaller terminals. A loading bridge must be easily adjustable to the different
distances during airport operation in order to service a number of different aircraft.
Therefore, there has continued to be a need for a highly adjustable and enclosed0 passenger or cargo loading/unloading bridge that can be advantageously utilized with
such small aircraft.
Large variation in the loading height of different common commuter aircraft, also
requires a loading bridge able to be adjusted over a wide range of heights. Currently
available loading gates cannot be lowered sufficiently to service smaller aircraft. It
would be advantageous to provide a passenger loading bridge that is capable of mating
with an airport at ground level and with small and large commuter aircraft.
In U.S. Patent 4,161,049 issued to Saunders et al. on July 17, 1979, a passenger20 loading bridge for a ground level terminal is disclosed. Saunders provides a fixed length
walkway which swings about a ground level rotunda. In order to accommodate smallaircraft, a stairway from the rotunda to the walkway is provided. The stairway permits an
end of the walkway proximate the terminal to be raised to or above the minimum height
of the supports for raising and lowering the end of the walkway proximate an aircraft and
25 therefor allows the walkway to mate with aircraft entrances that are disposed in line with
the minimum support height. The use of stairs to elevate the bridge is undesirable
because of limited access for the physically disabled and other liabilities associated with
stairs. Further, Saunders provides an extensible cab portion for aligning the door of the
aircraft to the loading bridge. However, the length of the bridge is not adjustable. As a
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
result all aircraft must be parked at the maximum distance from the terminal. Nosignificant adjustment to the placement of the cab of the loading bridge is possible.
When coupling available passenger loading bridges to aircraft such as jumbo jets,
5 a significant clearance exists between the engines and the aircraft entrance. Also, as the
entrance to a jumbo jet is displaced from the ground by a considerable distance, collisions
with personnel, baggage, or vehicles on the ground is unlikely. In contrast, the entrance
for a Dash 8 is less than 4 feet from the ground. An aircraft interface approaching the
entrance is susceptible to ~l~m~ging vehicles and hurting people. Also, because a small
o aircraft has significantly less clearance between the propellers and the entrance than
jumbo jets, current passenger loading bridges require several people to guide them into an
engaged position. It would be advantageous to provide a passenger loading bridge that
reduces a likelihood of ~l~m~gin~ an aircraft and increases personnel safety.
A typical loading bridge as disclosed in U.S. patent No. 3,462,784 to Seipos, for
large aircraft includes a number of telescoping sections. The assembly is pivotally
supported by the terminal at a first end. At the plane eng~ging end a wheeled gantry
supports the bridge at variable heights. The wheels are driven and steerable to extend the
bridge sections as necessary and to swing the gate to the correct position. Seipos has
20 found that the use of multiple wheels to support the assembly results in difficulties in
coortlin~ting the wheels to achieve the swing movements and extension-retractionmovements necessary to position the end of the loader at the airplane door. The lack of
accurate control over the gantry movement is termed ".~n~king". Snaking a loader into
position can result in damage to the airplane or the loader, and also results in lost time.
25 Seipos discloses a linkage to tie the movement of all wheels together. However, when
steering the wheels in tandem or even only one drive wheel, ~n~king can result. The
necessity to reposition the wheels from extension movement to swing movement means
that the wheels are not always in a known orientation. Some driving movement is
necessary to determine and to correct or steer the wheels. Steering or corrective
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
movement results in a compromise to the accuracy of the gate positioning at the aircraft.
As discussed above, particularly with smaller aircraft where the distance between the
door and propellers is quite small, any inaccuracy in positioning the loading bridge is
likely to result in costly damage to the aircraft. It is desired to provide a variably
adjustable loading bridge which can be positioned accurately, in a timely fashion without
the guidance of numerous personnel.
It is necessary to be able to position a loading bridge quickly and accurately over
widely varying distances and heights, without risk of (l~m~ging aircraft or injuring
ground personnel.
Summary of the Invention
The present invention has found that the use of two stages of movement to
position the gate of the loading bridge at the aircraft doorway results in efficient and
accurate placement, without risk of damage. A first extension movement adapts the
length of the bridge to the distance to the plane. This length must closely approximate
the distance without risking over-extension which would damage the aircraft, propellers,
etc. A second stage of extension then aligns the door without risk to the aircraft or
ground personnel. This method is preferably carried out by a loading bridge having two
separate telescopic extension assemblies: a first for adapting the length of the bridge, and
20 a second for positioning the aircraft interface section relative to the aircraft door.
Accordingly the present invention comprises a passenger loading bridge for
conducting passengers or cargo from an airport t~rrnin~l to an aircraft entry door of an
aircraft comprising:
an extensible walkway communicating at one end with the airport terminal and
having an aircraft eng~ging end at an opposite end;
drive means for extending the walkway to a desired length;
an extensible aircraft interface section coupled to the walkway at the aircraft
eng~ging end;
means for directing at least the aircraft interface section adjacent the aircraft; and
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
extension drive means for extending and retracting the aircraft interface section to
align a communicating port of the interface section with the aircraft entry door.
A preferred method according to the present invention comprises a method of
docking a passenger loading bridge to align a communicating port of a passenger loading
bridge with an aircraft entry door comprising the steps of:
determinin~ a distance to the aircraft entry door;
extending the walkway at a first rate to a length equal to the determined distance
o less a standard increment;
positioning an aircraft eng~ging end of the walkway adjacent the aircraft;
extending a communicating port at the aircraft eng;~ging end of the walkway at asecond rate to align with the aircraft entry door.
s In a further preferred embodiment the present invention comprises an extendable
loading bridge supported for pivotal movement about a first end for communication with
an airport terminal comprising:
a walkway including at least two telescopically extendable sections;
a rotunda supporting a first end of the walkway for pivotal movement about a
substantially vertical axis, the rotunda further including an entryway for communication
with the airport terminal;
a moveable support means for supporting an opposite end of the walkway
including
a first drive means for extending the telescopic sections of the walkway in a radial
2s path;
a second drive means for pivoting the opposite end of the walkway about the
rotunda in a arcuate path.
Advantageously the loading bridge according to the present invention can be
extended in an area away from plane servicing activity, prior to being pivoted into place.
Final extension for alignment correction is then made by the extendable interface section
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
without moving the drive wheels. This reduces danger to ground crew and equipment in
the area.
In addition advantageously extending the loading bridge according to the presents invention in two stages at first a coarse adjustment rate and finally a fine adjustment, the
bridge can be placed efficiently without risk to equipment or personnel.
Further it is an advantage of the present invention to utilize two separate drive
means for radial and arcuate movement resulting in accurate placement of the aircraft
lo interface.
Further advantages will be al~pa~elll to persons of skill in the art from the detailed
description with reference to the following drawings which illustrate preferred
embodiments of the invention by way of example only. Like numerals are used
throughout to refer to like elements.
Brief Description of Figures
Figure 1 is a plan view of a preferred embodiment of the present invention illustrated in a
fully extended position;
20 Figure 2 is a side view of the embodiment of Figure 1;
Figure 3 is a side view of an alternative embodiment according to the present invention in
a fully raised position;
Figure 4 is a reverse side view of the embodiment of Figure 3 in a fully lowered position;
and
2s Figure 5 is a plan view of the wheeled gantry in isolation.
Detailed Description of Preferred Embodiments
The loading bridge according to the present invention is shown generally at 10 in
30 Figure 1. The bridge 10 is supported at a terminal end 31 by a rotunda 20. The rotunda
20 communicates with the airport terminal (not shown) through a simple passageway, or
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
an additional walkway of desired length (not shown). The rotunda 20 is fixed andsupports the terminal end 31 of the enclosed bridge walkway 30 for hinged movement
about a horizontal axis for height adjustment, and also for pivotal movement about a
vertical axis through the rotunda 20. The rotunda 20 may be supported on a raised
5 platform as shown, or may be directly at the ground level. Rotation may be about a
central axis or an eccentric axis. The rotunda 20 remains enclosed by flexible curtains
during movement of the passenger loading bridge 10 maintaining protection from the
elements. Walkway 30 includes two telescopic sections 32,34 which provide an
expansion of approximately 20 feet. If more expansion is necessary additional
0 telescoping sections may be added.
Adjacent an aircraft eng~ging end 33 the walkway 30 is supported by a wheeled
gantry support means 40. The wheeled gantry 40 is powered to drive the aircraft
eng~ging end 33 through the arc shown, while the t~rrnin~l end 31 pivots about the
15 rotunda 20. The wheeled gantry 40 also includes standards 42 to either side of the
walkway 30 comprising mechanical screw jack lifts for raising and lowering the height of
the aircraft engaging end 33 of the bridge 10. Other means such as hydraulic drive can be
used to raise the bridge 10. The mechanical lifts 42 are preferred as they provide braking
in the event of drive failure. Standards 42 are angled with their uppermost ends inclined
20 toward the aircraft en~gin~ end 33. This angle reduces lateral drag on the tires as the
bridge 10 is raised to prevent excessive wear. As better seen in Figure 5, the wheels 44
of the gantry 40 are arranged in angled pairs along radial axles to follow a radial arc path
The wheels 44 are supported by axles 46 disposed above the frame 48. The placement of
the wheels 44 above the gantry frame 48 allows a simple rectangular frame construction
25 and permits the aircraft interface section 60 to be lowered to a level nearer the ground.
Further, the gantry configuration allows for large gantry wheels 44 without raising the
minimum height substantially. Since the gantry frame 48 extends beyond the sides of the
bridge 10, the gantry 40 is positioned behind the aircraft interface section 60 by a
sufficient distance to clear any steps, railings, and propellers of supported aircraft in order
30 to prevent any potential collision with the gantry wheels which could cause damage.
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
Additional support is provided by radial wheels 50. Gantry wheels 44 may be
raised, as shown in Figure 2, leaving the bridge supported on radial wheels 50. Radial
wheels 50 are positioned substantially perpendicular to gantry wheels 44. Separate drive
to the radial wheels 50 is used to telescopically extend or retract the length of the
5 walkway 30. Once a desired length is achieved, the gantry wheels 44 are again lowered
to support the bridge 10. Separating extension drive from rotational drive allows the end
of the bridge to be rotated into very closely accurate position without introducing error
which might risk collision. When the drives are unified in a steerable gantry, ~n~king can
occur which introduces error in the extension or positioning, and further slows the
0 docking operation.
At the aircraft en~ging end 33 an aircraft interface section 60 is telescopically
supported within the walkway structure 30. This telescoping section 62 permits an
additional 8 feet of extension of the bridge 10 for accurate alignment of the aircraft
interface section 60 and the aircraft entry door, without further positioning of the major
supports 40 and 50. In addition the communicating port 64 which aligns with the aircraft
entry door (not shown) is pivotally adjustable about rotational section 66 to make final
alignrnent adjustment, as shown in Figure 1. Preferably pivotal alignment of thecommunicating port 64 is made prior to the final extension of telescoping section 62. In
20 this way very little clearance is needed to position the communicating port 64 at the
aircraft entry door, reducing the risk of contacting the propeller. A canopy 68 is
extended and deformed to conform to the outer shape of the aircraft to provide a weather
seal. Two separate actuators are needed to extend the canopy and change the radius of
curvature to accommodate aircraft which vary considerably in dimensions.
2s
Final adjustment movements of the rotational section 66 and telescoping section
62 occur above ground level. Thus once the rough placement of the bridge is madecollision of the bridge drive with other servicing operations is no longer a risk, and
additional servicing can continue while final docking is completed. Controls for the
30 passenger loading bridge 10 are located within the aircraft interface section 60 proximate
CA 02240042 1998-06-09
Doc. 12M-3 CA Patent
the bumper 69 to allow for accurate docking. Windows in the interface section 60provide the operator a clear view of engines or propellers and the aircraft fuselage.
In operation an arriving aircraft is identified to determine height requirements and
5 expected docking distance. The gantry 40 is fully lowered and the wheels 44 are lifted to
place the bridge 10 on the radial wheels 50. Drive to the radial wheels 50 extends the
telescoping sections 32,34 of the walkway 30 to a length equal to the distance to the entry
door or slightly less. Conveniently a standard adjustment increment well within the
expansion range of the interface section 60, is used to reduce the extension of the
o walkway 30. The gantry wheels 44 are again lowered to support the bridge again raising
it offradial wheels 50. The aircraft eng~gin~ end 33 is raised on standards 42 to the
correct height for the aircraft. Drive to the gantry wheels 44 rotates the aircraft en~;~ging
end 33 about the rotunda 20 until the interface section 60 is adjacent the aircraft. Angular
adjustment to the alignment of the aircraft is made by rotating the communicating port 64
about rotation section 66. Then a final extension from the telescoping section 62
advances to position the communicating port 64 at the aircraft entry door.
Figure 3 illustrates an alternative embodiment of the invention at full height
position. Figure 4 illustrates the same embodiment at its lowest position.
Numerous other embodiment of the invention will be apparent to persons skilled
in the art without departing from the spirit and scope of the invention as defined in the
appended claims.
