For a long time, it was a critical moment to both passengers and streetcar personnel when the doors of the Cobra series of streetcars in Zurich were closing. These vehicles featured a photoelectric sensor mounted near the floor in order to signal when a person or object was present in the pivoting area of the doors. It accomplished this purpose, but was unable to recognize when a boarding passenger wanted to pull himself or herself into the car at the last minute by grabbing on to the handrails next to the doors. So, the doors would close, which in many cases gave a fright to passengers or - worse - sometimes even injured them on the arms, despite the rubber linings on the door leaves.
About two years ago, these experiences resulted in us deciding to protect the door areas better in order to avoid the doors closing while a person was boarding or getting off, Viktor Zürcher, Project Manager Vehicles at VBZ looks back. With more than 200 million passengers a year boarding the trains, this constitutes a top priority.
Viktor Zürcher, Project Manager Vehicles VBZ
Convincing safety solution
The safety task was clear: recognizing humans and objects at the height level of the handrails. Together with SICK, Viktor Zürcher also analyzed the operating environment: varying light conditions during the day and at night at more than 400 stops, fluctuations in temperature between summer and winter, backlighting, deliberate blinding, rain and snow, vibrations during vehicle operations, misalignment-proof installation in the door area - it was necessary to consider all of these aspects for safe operation.
The decision went in favor of the C2000 safety light curtain from SICK. The product is an electro-sensitive safety device tried and tested in harsh industrial environments serving to protect hazardous areas; its sender and receiver generate a protective field in the door passage. As soon as one or more doors are open, the safety light curtains become active. They check for every door whether someone or something is still located within the door entrance. If that is not the case, the door closes. If so, a warning signal sounds, and the door control stops the closing action.
C2000 safety light curtain
- Product information: C2000 safety light curtain
- Product portfolio: Safety light curtains
