Blocking apparatus for a fire damper, blocking apparatus system and method for blocking a drive direction

A blocking apparatus system, comprising:

• a holding apparatus;
• a receiving element rotatably mounted in the holding apparatus about an axis of rotation, the receiving element defining a through-opening with a through-axis coaxial or parallel to the axis of rotation;
• a wrap spring held mechanically prestressed in the holding apparatus, with at least one winding arranged around the receiving element;
• and
• a thermocouple made of a material having a lower melting temperature than a lowest melting temperature in the holding apparatus and/or than a melting temperature of the wrap spring;
• wherein the thermocouple holds at least one end of the wrap spring with respect to the holding apparatus in the prestressed state in such a way that the receiving element can be freely rotated in both drive directions about the axis of rotation;
• and
• the receiving element is blocked in one of the two drive directions in the relaxed state of the wrap spring and in the triggered state of a thermal fuse;
• and
• a fire damper;
• wherein the blocking apparatus is arranged on a drive element of the fire damper;
• and the fire damper is to be kept closed in the event of a fire.

A method for blocking a drive direction of a drive element for a fire damper, the method comprising:

• arranging a wrap spring around a drive shaft driven by a drive unit;
• prestressing the wrap spring using a thermocouple;
• wherein the thermocouple, in the event of a fire or in the event of overheating of a machine, decreases in strength or melts, with the prestressed wrap spring relaxing as a result;
• wherein a material of the thermocouple has a lower melting temperature compared to a melting temperature of the wrap spring;
• wherein the relaxed wrap spring has a smaller internal diameter than the prestressed wrap spring;
• wherein the wrap spring, due to the reduced internal diameter, blocks rotation of the drive shaft in the drive direction, and allows it in an opposite direction of rotation.