Stretchable sheet-like hangings or stretchable covers
It can be seen according to its patent drawings. Is this an expression?
Extension - extended, stretchable.
flap - 1. Flap-shaped hanging object 2. Beat, slap 3. Excited, panic state 4. Flat hanging object (attached to something), seal, flap, bag lid 5. Public disapproval; public anger; public criticism 6. Flaps (of aircraft)
If it is mechanical, it can be translated as: extended cover to see if it matches the component name on the drawing