Options for Mechanical Hold Force for Sliding Doors

Abstract: ASSA ABLOY’s automatic sliding doors today have a constant hold force applied whenever the doors are closed. The force is adjustable between 0-60 N and is generated by a motor. In this project it has been investigated whether it is possible to install a mechanical alternative to this hold force instead. The project was initiated by ASSA ABLOY, who also has been providing the data and information needed in order to work with the project. After investigating many different options, a solution was decided upon which uses magnets and springs. A prototype of this solution has been made as a proof of concept. This solution is seen as possible to use in future doors and also gives the opportunity to integrate with a night lock. There is some doubts regarding if this solution should be recommended to all users of ASSA ABLOY’s doors. An argument is presented that doors which are opened with a high frequency are better left with the motor as a hold force generator since a mechanical solution will only interfere and make a quick turn in the opening and closing sequence slower. All solutions presented are in need of more development, though a proof of concept has been made for the suggested solution. There is a need for an economical analysis and a material analysis in order to get on further with the project. Also more research needs to be done in finding the right magnets and springs, both in size and in force.