Tiggerbottom Doorframe

... tiggers are wonderful things!
Their tops are made out of rubber
Their bottoms are made out of springs!


OK, so even by Dell House standards this was unexpected.  One bedroom door frame had an extra 'inner frame, seemingly bolted on with small metal plates.  This wasn't pretty so as part of the pre-prep for the decorating, this was coming off.

Oh, so the plates aren't plates but... springs?!

Transpires that this extra frame was supposed to move to form a tight seal with the door.  Liberal sloshings of paint had put paid to that theory but the back of the timber was lined with velvet for ease of movement.  (See extra).  The brass units are quite precisely engineered so it looks commercial. The state of the paint on the underside is in good condition but very 'flat' and thin - I'd guess from the first half of last century.

I'm uncertain what the intention of the mechanism was.  The immediate thought was that was some form of fire sealing in lieu of / preceding intumescent strips but it seems odd that only one of ~25 similar doors has any sign of this being fitted and it's not a critical door, just a side room that was probably a dressing room for one of the main bedrooms originally.  

Thus, thoughts go to light sealing but this is one of the south facing rooms so the window would be a far bigger problem, or sound insulation, or draught insulation?  No idea.