US 11,753,275 B2
Method for preventive maintenance of an elevator and an elevator system
Matti Mustonen, Helsinki (FI); Arttu Leppäkoski, Helsinki (FI); Ari Jussila, Helsinki (FI); and Juha-Matti Aitamurto, Helsinki (FI)
Assigned to KONE Corporation, Helsinki (FI)
Filed by KONE Corporation, Helsinki (FI)
Filed on Jan. 22, 2019, as Appl. No. 16/254,243.
Claims priority of application No. 18156867 (EP), filed on Feb. 15, 2018.
Prior Publication US 2019/0248625 A1, Aug. 15, 2019
Int. Cl. B66B 5/00 (2006.01)
CPC B66B 5/0025 (2013.01) [B66B 5/0031 (2013.01); B66B 5/0037 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for preventive maintenance of an elevator speed sensor system comprising at least a first and a second sensor, which are independent of each other, the method comprising:
determining a reference distance for an elevator car travel between a first door zone and a second door zone;
during an elevator car travel between the first door zone and the second door zone, defining continuously first elevator car speed information from the first sensor and second elevator car speed information from the second sensor;
calculating a cumulative sensor system error by integrating a difference between the first elevator car speed information and the second elevator car speed information; and
dividing the cumulative sensor system error with the reference distance to obtain a sensor system performance indicator.