Articulated bridge

Details Articulated bridge Articulated bridge

1999-10-04

2001-09-25

Will, Thomas B. (Department: 3673)

Bridges

Gangway, ramp, or dock leveler

Attached

C014S069500, C104S031000, C104S133000

Reexamination Certificate

active

06292968

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to the field of bridges, and more particularly to an apparatus and method for joining a movable structure to a fixed structure
BACKGROUND OF THE INVENTION
There are many applications in which it is necessary or desirable to join a movable structure to a fixed structure to provide access to the movable structure while allowing movement of the movable structure relative to the fixed structure. For example, it is often necessary to provide access between a ship and a pier or an aircraft and an airport terminal. This is particularly a problem for motion-bases that typically include a “base” or platform that can provide for six degrees of freedom of motion including roll, pitch, yaw, vertical, lateral and longitudinal motion. Motion-bases are widely used in devices such as vehicle simulators, amusement rides and interactive theaters which move in synchronization with images projected on a screen to create the illusion of riding in a particular vehicle.
It will be readily appreciated that the complex movement of the motion-base makes it impossible to use rigid bridges having fixed dimensions and orientation to join it to a fixed structure. Moreover, a bridge or gangway that is not anchored at one end but in sliding engagement with the motion-base or the fixed structure, such as a brow joining a ship to a pier, is also generally not satisfactory because it cannot allow for simultaneous rotation about or movement along multiple axes. For example, while a ship's brow is frequently made to allow for some lateral motion away from and toward the pier, and may even be hinged to allow for moderate rolling motion, it would not allow for a pitching motion that would cause opposite sides of the brow to lift alternately. Thus, prior art solutions for providing ingress and egress to a motion-base while allowing it to move relative to a fixed structure have focused on movable ramps or platforms moved into position after the movement has been stopped to allow access to and from the motion-base.
One proposed solution, shown in
FIGS. 1 and 2
, utilizes five parallel planks
20
extending from the fixed structure
25
to the motion-base
30
to form a gangway
35
. The planks
20
are joined to one another by an tongue-and-groove arrangement
40
that allows adjoining planks to be moved in opposite directions as indicated by arrows
45
. Each plank
20
is coupled to either the fixed structure
25
or the motion-base
30
in such a manner that no two adjoining planks are both connected to the same structure. The planks
20
are rigidly connected to the fixed structure
25
through a first bar
50
, and are connected to the motion-base
30
through a second bar
55
and a pivot
60
. While an improvement over ramps which are manually moved into position this design is not completely satisfactory.
A problem with this approach is it severely limits the freedom of movement of the motion-base
30
. In particular, the rigid attachment to the fixed structure
25
prevents the gangway from allowing longitudinal movement of the motion-base in a direction perpendicular to the gangway
35
. For the same reason, the gangway
35
does not allow a yawing motion or a purely vertical movement of the motion base
30
. This design might allow a limited rolling motion of the motion base
30
, provided the roll axis coincides with the axis of the pivot. In fact, the only movement of the motion base
30
that the gangway clearly would allow is a lateral movement towards or away from the fixed structure
25
. A further problem with the gangway shown in FIG.
1
and
FIG. 2
, is the difficulty and expense of forming the tongue and groove arrangement
40
. Moreover, this design allows dirt or other foreign objects to fall into the tongue and groove arrangement
40
, which can cause the planks
20
to bind and rendering the gangway
35
inoperable.
Another prior art solution, as disclosed in U.S. Pat. No. 5,277,662, to Fox et al., hereby incorporated by reference, use movable platforms pivoted into position to load and unload passengers from a motion-base, here an amusement park ride, and folded away from the motion-base while it is in operation. Although this approach avoids many problems of rigid bridges and sliding gangways, it leads to several additional problems, and therefore is also not completely satisfactory.
One problem with this approach is the added cost and complexity of a controller required to return the motion-base to a precise position relative to the fixed structure. The controller is also needed to synchronize the movement of the platform to that of the motion-base so that the platform is moved into position as soon as the motion-base stops. In addition to the cost, the controller also adds to the maintenance requirements and the potential for malfunctions. Moreover, for many applications, such as an amusement ride, the time delay occasioned by extending or folding away the platform before and after operation of the motion-base is very undesirable.
Another, more serious problem with all such solutions is that the passengers are effectively trapped on the motion-base for the duration of the ride. While many passengers would probably be unaware of this, or at most would be only slightly inconvenienced, in case of fire or a medical emergency the situation could be life-threatening. Moreover, if, as in the reference cited above, the platform is automatically or electronically controlled the problem is exacerbated during a power failure.
Yet another problem with the above approach, is the potential for injury by the movable platform. If the platforms do not couple with the fixed structure or the motion-base closely enough, a passenger can fall through or have a limb or clothing become trapped in the resulting gap.
Accordingly, there is a need for an apparatus and method for joining a movable structure to a fixed structure to provide access to the movable structure while allowing movement of the movable structure relative to the fixed structure. The present invention provides a solution to these and other problems, and offers other advantages over the prior art.
SUMMARY OF THE INVENTION
The present invention provides an apparatus and a method for joining a first structure to a second structure. In one embodiment, the present invention provides a bridge for joining a movable structure to a fixed structure. The bridge includes a number of spaced apart extensible beams, each extensible beam having a first end pivotably and rotatably attached to the movable structure and a second end pivotably and rotatably attached to the fixed structure. A number of deck members are supported above and by the extensible beams in a substantially horizontal attitude, each of the deck members pivotably and rotatably attached to one of the extensible beams to provide ingress and egress to the movable structure. In one version, the movable structure is a vehicle, and the first ends of each of the extensible beams are releasably attached to the vehicle. The vehicle can be a train, an automobile, a watercraft, an aircraft, or a spacecraft.
In another embodiment the present invention is directed to a bridge for joining a motion-base to a fixed structure to provide ingress and egress to the motion-base. The bridge includes three spaced apart, extensible beams including a central extensible beam and two outer extensible beams, one on each side of the central extensible beam. Each extensible beam has a first end pivotably and rotatably attached by a spherical-swivel-joint to the motion-base and a second end pivotably and rotatably attached by a spherical-swivel-joint to the fixed structure. Deck members are supported above and by the extensible beams in a substantially horizontal attitude, each deck member is pivotably and rotatably attached by a ball-socket-joint to the central extensible beam and in sliding contact with the outer extensible beams. Optionally, each of the deck members further includes several pads of material having a low coefficient of friction between the deck

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