Strain sensor for a position measuring tape of an elevator

A sensor apparatus for an elevator with a hanging position measuring tape for detecting a critical change in length of the position measuring tape comprising:

• a carrier with a mounting element for mounting the carrier on a stationary part of the elevator, the carrier comprising a carriage and a tape holder on the carriage with at least one securing element for securing the position measuring tape in a fixed location and for roughly setting the length position of the position measuring tape,
• a guide device between the carrier and the carriage with guide elements on the carrier and on the carriage for, in the parallel direction of the position measuring tape to be mounted, displaceably securing the carriage to the carrier,
• a tensioning device between the carrier and the carriage with engagement elements on the carrier and the carriage and with a tensioning element which is secured to the engagement elements in order to move the carriage counter to the direction of the positioning tape to be secured and in order to be able to tension a secured positioning tape,
• a detection device for detecting a critical displacement of the carriage on the carrier on the basis of a critical change in length of a position measuring tape to be mounted and for outputting a signal in the event of a detection, with at least one activation element for identifying the position of a critical displacement and with a sensor for detecting the activation element in the event of a critical displacement, wherein the activation element and the sensor are alternately secured on the carrier and the carriage, and
• an adjusting device provided in order to be able to set the distance between the at least one activation element and the sensor, with at least one adjusting element on the carriage and the tape holder for setting the position of the tape holder with respect to the carriage in a parallel direction of the position measuring tape to be mounted in order to be able to adjust the length position of a position measuring tape to be mounted with respect to the carriage, or on the carrier and the carriage for setting the distance between the at least one activation element and the sensor.