Damper blade operating mechanism

A fluid damper assembly comprising:

• (a) a duct through which fluid flows when the duct is in use;
• (b) a fluid damper extending across said duct;
• (c) blades of said fluid damper movably mounted therein to affect flow through said duct;
• (d) a blade release mechanism arranged on the outside of said duct and connected to said fluid damper so as to be capable of releasing said blades from positions which they normally occupy;
• (e) wall portions of said duct defining an opening therein;
• (f) a fusible actuating cartridge arranged to act on said blade release mechanism to release the blades from their normal positions if and when fire breaks out, said fusible actuating cartridge projecting through said opening in said duct so as to be readily removable from said duct;
• (g) a spindle of said fusible actuating cartridge;
• (h) a button on an end of said spindle;
• (i) a triggering member of said blade release mechanism;
• (j) an aperture-defining part of said triggering member, said spindle extending through the aperture in said triggering member;
• and
• (k) means to urge said button on said spindle against said aperture-defining part of said triggering member to actuate said blade release mechanism if and when fire breaks out, said aperture-defining part also being movable away from said button to actuate said mechanism independently of said cartridge.