Conveyors: power-driven – Conveying apparatus entirely supported by mobile ground... – Conveyor shiftably mounted on vehicle
Reexamination Certificate
2004-02-26
2004-10-26
Hess, Douglas (Department: 3651)
Conveyors: power-driven
Conveying apparatus entirely supported by mobile ground...
Conveyor shiftably mounted on vehicle
C198S300000, C198S316100, C198S321000
Reexamination Certificate
active
06808057
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an escalator, and more particularly to a mobile escalator. The truck-mounted escalator has particular utility in connection with providing a mobile escalator which can easily be moved from place to place and quickly positioned for user access, such as at airplanes that are parked away from the typical loading platform.
2. Description of the Prior Art
Mobile passenger stairways are used in airports to comfortably assist passengers in debarking from the plane when the arrival or departure gate is not elevated above ground level. They are more common in medium size airports with short-hop commuter jet service but are also used to a lesser extent at larger airports when the arrival or departure gate is at the tarmac level. Existing mobile passenger stairways can be configured on a manual dolly base with locking wheels, or they can be mounted upon a motorized truck chassis. However, the existing mobile passenger stairways all share the aspect of having individual steps that are permanently fixed in location. Due to the height of the airplane above the ground, these passenger stairways are typically quite steep. Climbing such a stairway could pose a strenuous and forbidding task for passengers with age or health related infirmities as well as those with physical limitations. Additionally, the steepness of the stairs could lead to passengers slipping and falling due to loss of balance. Therefore, a passenger stairway that functioned identically to escalator stairs would make debarking from planes to the ground a safer, more acceptable procedure for all passengers.
The use of portable escalators is known in the prior art. For example, U.S. Pat. No. 2,929,482 to Floyd Coryell discloses a portable escalator having an upper platform that may be hydraulically raised or lowered and a stationary lower platform. The portable escalator consists of a movable ramp, which might include steps, that is rotated by an electrically driven belt and pulley assembly. The entire escalator assembly is mounted on a movable platform with a pair of front wheels and a pair of rear wheels, at least one of which includes a pulley engaged by a drive belt, which is in turn driven by a pulley carried by the drive shaft of a suitable electric motor. However, the Coryell '482 patent utilizes collapsible supports for the escalator unit which could lead to possible collapse of the entire structure if the supports are not properly positioned with each use. This would require an additional safety check each time the escalator assembly was positioned for use. Furthermore, the complexity of the belts and pulleys of the Coryell '482 device would increase the necessary maintenance for the device as well as increasing the chances of mechanical failure.
U.S. Pat. No. 3,033,340 to Floyd Coryell is a continuation of Coryell '482 and further discloses his portable escalator. This escalator is gear driven and is raised and lowered by an electrically operated elevator in the form of a pair of screwjacks. However, in order to keep the links of the conveyor taut, the floor of the upper end platform of the Coryell '340 device could not be maintained horizontally for some angles of inclination of the escalator. This could disorient passengers, causing them to lose their balance, when stepping off the escalator onto the platform or from the plane onto the platform. Additionally, the Coryell '340 patent relies on pin and slot connections to securely engage when the escalator is raised. This increases the chances of mechanical failure, which could lead to the subsequent collapse of the escalator.
Similarly, U.S. Pat. No. 2,967,602 to Russell B. Mosier discloses a boarding apparatus for aircraft that includes a sprocket driven conveyor with handrails that is mounted on a dolly or similar mechanical device. However, the Mosier '602 patent fails to provide an electrical source to power the device; therefore, the boarding apparatus could be utilized only near an acceptable power source. In addition, changing the inclination of the Mosier '602 device requires the user to operate a hand wheel. This could be an awkward and cumbersome task for individuals with limited arm or hand strength and could take a considerable amount of time in a trial and error process to properly position the boarding apparatus.
U.S. Pat. No. 4,759,437 to John R. Bevins discloses a handrail for an aircraft belt loader in which a pair of parallel support arms pivotally supports a rigid rail member. The handrail is collapsible and relies on a compression spring to fully erect the device when it is operative. However, due to the collapsible nature of the Bevins '437 device, an incomplete or improperly locked support arm could lead to collapse of the device upon application of the weight of a debarking passenger leaning upon the rail for support. In addition, the support arms of the Bevins '437 device are spaced far enough apart to allow a passenger, such as a small child or one who lost his footing, to fall through to the ground below.
Likewise, U.S. Pat. No. 4,574,937 to James M. Anderson and William C. Dean discloses a multi-positionable rail for the conveyor of an aircraft belt loader. The rail would be supported by a plurality of parallel posts pivotably connected to the side wall of the conveyor and rail and collapsible under the force of gravity. However, the Anderson, et al. '937 patent uses posts that are collapsibly and pivotably connected to the conveyor. This would require human intervention to verify the structure prior to each use since incorrect positioning or insufficient locking of these posts could cause injury to an individual placing any weight or stress upon them. Furthermore, the rails of the Anderson, et al. '937 device are spaced far enough apart that a young child or an individual who tripped or lost his footing in some manner could potentially fall through the opening to the ground below.
Lastly, U.S. Pat. No. 3,543,917 to Arnold Duersken discloses an inclined elevator conveyor wherein a series of horizontal platforms, articulated in sections, travel an inclined, reversible cyclic path. The leading end of each platform moves out of the way of the cargo on the platform, while the trailing end of each platform continues to follow the cargo as it is discharged onto a cargo receiving table. The direction of cargo movement is varied by variously directing the table. However, while the Duersken '917 patent provides for the movement of cargo along the conveyor, it does not provide a suitable means for moving people along the same conveyor. The roller arrangement used to propel the conveyor and the buckets used to stow the cargo during transport would not be suitable for use by individuals entering or exiting an aircraft. Additionally, the Duersken '917 device is comprised of collapsible support members, which could collapse if not properly locked into place when the conveyor was placed in an inclined position. Finally, the Duersken '917 patent fails to provide a hand rail which would prevent passengers from falling from the conveyor device.
While the above-described devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe a truck-mounted escalator that provides an easy-to-use and portable escalator for allowing airline passengers a safe and physically undemanding means for entering or exiting an aircraft that is parked on the tarmac. The Coryell '482, Coryell '340, Bevins '437, Anderson, et al. '937, and the Duersken '917 devices are all comprised of collapsible components which would require constant supervision to ensure that all parts are correctly positioned to avoid collapse of the structure. Furthermore, the complexity of the belts and pulleys of the Coryell '482 device would increase the necessary maintenance for the device as well as increasing the chances of mechanical failure. The Coryell '340 de
Nirmal Jitendra R.
Nirmal Ravi J.
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