the fuse is not blown out either.
The pin and a small spiral spring (which is probably under your sofa now) are loosely under the ceramic - so always pay attention to them when removing them
If the temperature of the heating rises above the trigger temperature of the fuse, the spring pushes the pin upwards through the fusible link and interrupts the contact.
If you can't find the spring you need a new fuse.
Here the data:
trip temperature is 206°C,
manufacturer is "Inter Control" and is called as single product "Minimelt"
Buerklin.en under art.no. 30G4420.
The other two elements on the rail are not fuses but thermostats by the way.