Door Wing Safety Stop for Public Transport Vehicles
Solution Overview
Problem
Existing door devices for public transport vehicles often fail due to breakage of the pin supporting the wheel at the lower end of the door wing, leading to unsafe outward swinging of the door wing, posing a risk to passengers and other vehicles or people.
Innovation Solution
A safety device with a stop element mounted on the stationary door structure to prevent the door wing from rotating outward beyond a predetermined angle in case of disengagement, accompanied by a sensor for alarm signaling and an electrically-operated actuator for adaptive operation based on vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the door wing is connected to the door opening control device at only two points (upper and lower ends), then the device complexity is reduced, but the reliability deteriorates due to risk of disengagement
Solution Approach 1:
The patent applies preliminary anti-action by providing a stop element that prevents the door wing from swinging outward beyond a predetermined angle. This stop element is positioned in advance to counteract the harmful effect of disengagement before it can cause complete loss of control. The stop element creates a mechanical barrier that limits the outward movement of the door wing, thereby maintaining safety even when the engagement member disengages from the guiding track.
2Reliability
If a stop element is added to prevent door wing rotation, then the reliability improves, but the device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a stop element that acts as a mediator between the door wing and the stationary structure. This stop element serves as a simple mechanical intermediary that limits the outward movement of the door wing without requiring complex control systems. The stop element is carried by the stationary structure and engages with the door wing-supporting arm to prevent excessive rotation, providing a straightforward solution that adds minimal complexity while significantly improving reliability.
3Reliability
If the stop element is always active, then the safety is maximized, but the ease of operation deteriorates due to potential interference with normal door movement
Solution Approach 1:
The patent applies dynamics by making the stop element movable between an operative position and an inoperative position. The stop element can be moved to the inoperative position during normal door operation to avoid interference with smooth door movement. When disengagement is detected or under specific operational conditions, the stop element moves to the operative position to provide safety protection. This dynamic positioning allows the system to adapt between normal operation mode and safety protection mode, maintaining both ease of operation and reliability.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~5
AI summary
A door device for public transport vehicles, such as buses, trams or the like, comprises at least one door wing (4) having an upper end connected to a door wing-supporting arm (5) protruding from a bushing (6) mounted on an upper horizontal guiding rod (7). A vertical shaft (8) is rotatably supported on one side of the doorway, and carries a lower arm (9) at its lower end for guiding the door wing, which is operationally connected to a lower end of the door wing (4) by means of an engagement member in the form of a wheel (10) guided within a horizontal track (11) carried by the lower end of the door wing (4). In case of breakage of the pin of the aforesaid wheel engagement member (10), and the consequent release of the lower end of the door wing (4) from the lower guiding arm (9), an outward swinging of the door wing (4) around the axis of the aforesaid horizontal guiding rod (7) is prevented by a safety device (13) including a stop element (12) mounted on the stationary structure of the door, and configured and arranged to come into contact with the door wing-supporting arm (5) in order to prevent the above rotation. In a variant, the stop element is supported by the vehicle structure in such a way as to be movable between an operative position and an inoperative position, by means of an electrically-operated actuator. In this variant, the stop element is only kept in its operative position when the vehicle speed is above a predetermined threshold value, for example in the order of 5 km/h.