Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1999-02-25
2001-01-23
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C105S443000, C105S447000, C280S163000, C280S166000, C414S021000, C182S082000, C182S088000
Reexamination Certificate
active
06178364
ABSTRACT:
COPYRIGHT NOTICE
This document is copyrighted ©1999 Freightliner Corporation. A portion of this disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
BACKGROUND
The present invention relates to a method and apparatus for controlling the operation of a retractable stairway assembly for a vehicle such as a truck, the stairway being deployable for use in entering and exiting the vehicle and being stowable when not in use.
The design of many large vehicles, in particular cab-over-engine trucks, does not allow easy access into the cab of the vehicle. Often, the cab is positioned at a substantial height above the ground, making it difficult for a driver or passenger to enter and exit the cab. Therefore, steps or some type of foot support structure are often provided for use by an individual when climbing up into the cab as well as when exiting from the cab.
Although various approaches have been used to facilitate the entry and exit of an individual from a vehicle, a need nevertheless exists for a control method and apparatus for a retractable stairway assembly wherein the method and apparatus are novel and non-obvious improvements ways.
SUMMARY
A method of controlling retractable stairway assembly for a vehicle is disclosed. The vehicle may be of a type having a cab, the cab having an exterior and an interior. The cab also may have a cab sidewall within which a doorway and door is positioned. Access through the doorway is provided for ingress and egress into and out of the cab interior when the door is open. The retractable stairway is shiftable from a stowed position to a deployed position, when deployed the stairway is positioned for climbing along the stairway to and from the doorway.
The stairway may be shiftable between the deployed and stowed positions by pivoting the stairway between such positions, laterally extending the stairway from a stowed to a deployed position, or otherwise.
In connection with one aspect of one embodiment of the method, at least one vehicle status condition is evaluated from a set of vehicle status conditions, the set of vehicle status conditions including at least one of the following: (a) whether the vehicle is stopped, (b) whether the parking brake is set, and (c) whether the cab is tilted, for example from horizontal in excess of a threshold. If said at least one vehicle status condition is not in a predetermined state, deployment of the stairway is blocked.
The set of vehicle status conditions may comprise all three of these vehicle status conditions, two of the three conditions, or only one of these conditions as well as additional or alternative conditions. The predetermined states may be the truck is stopped, the parking brake is set, and the cab is not being tilted excessively.
In accordance with another embodiment, deployment of a stairway may be blocked if a manually actuated disable control, such as a switch, is in a step deployment or movement deactivating state. One of such manually actuated disable controls may be located within the interior of the vehicle. Another of such manually actuated disable controls may be located at the exterior of the cab. In one embodiment, the exterior disable control may be shifted automatically out of the step movement deactivating state after a predetermined period of time.
Although a semiautomatic control approach may be used, in accordance with a specific embodiment, deployment of the stairway from a stowed position toward a deployed condition commences upon opening of the cab door if said at least one vehicle status condition being evaluated is in the predetermined state.
An actuator, such as an electric motor, may be used to shift the stairway between stowed and deployed positions. In the event current delivered to the motor exceeds a threshold, deployment of the stairway may be blocked or interrupted. In accordance with the method, a variable current threshold may be established which is correlated with the position of the stairway. The current threshold may vary so that it is different for one position of step deployment in comparison to another position of step deployment. In addition, the threshold may vary over time such that it differs for one position of deployment at one time in comparison to the threshold for the same position of deployment at a different time. In addition, the current threshold may vary for a given position of step deployment depending upon whether the stairway is being stowed or deployed when at the position of deployment. In a specific approach, the travel of the stairway may be subdivided into a plurality of travel segments between the stowed and deployed position. A current threshold may be established for each of the travel segments and may comprise the sum of a stored average of current over time for the segment together with a current tolerance for the segment. The measured current for the segment nay be compared with the sum of the stored current average and the tolerance. If the measured current average exceeds the sum, an excess current condition is indicated. In this case, operation of the stairway may be halted. The sum of the stored current and average tolerance may be set to be less than or equal to a software imposed maximum tolerant limit. Under certain conditions, the software tolerance limit may be exceeded to accelerate closing of the stairway or provide more closing force. In addition, the method may include evaluating at least one interrupt deployment of stairway condition from a set of interrupt deployment stairway conditions. The set of interrupt deployment of stairway conditions may include at least one of the following: (a) whether a manually actuated exterior disable control at the exterior of the cab is in a step movement deactivating state, and (b) whether the speed of deployment of the stairway is below a threshold speed. The deployment of the stairway may be interrupted if said at least one interrupt stairway deployment status condition is not in a predetermined state.
Interior and exterior alarm devices may be activated in accordance with the control method under certain conditions. For example, an exterior auditory alarm may be activated at any time the stairway is being moved. Interior alarms or alerts, which may include an auditory alarm as well as a visual alarm such as a lamp, may also be activated under certain conditions. For example, the interior alerts may be activated in the event deployment of the stairway is interrupted due to excessive motor current being required by an electric motor used to extend and retract the stairway. Alternatively, interior alerts may be activated in the event said at least one vehicle status condition is not in a predetermined state.
In accordance with another aspect of an embodiment, the deployment of the stairway may be interrupted by closing the door.
In another embodiment, the stairway may be stowed from a partially or fully stowed deployed and toward a stowed position in the event at least one of the following vehicle status conditions occur: (a) the vehicle starts moving, and (b) the parking brake is not set. In accordance with this latter aspect of the method, both of these status conditions need not be monitored, as either of these conditions may be monitored in the alternative.
The present invention is directed toward novel and non-obvious aspects of a retractable stairway control method as set forth above and in the following description and drawings individually, as well as collectively.
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patent: 3224525 (1965-12-01), Froitzheim et al.
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patent: 36
Blakewood, Jr. Charles H.
Delurey Paul J.
Johnston David J.
Massey, III William G.
Mayenburg Michael von
Beaulieu Yonel
Cuchlinski Jr. William A.
Freightliner Corporation
Klarquist Sparkman Campbell & Leigh & Whinston, LLP
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