Expansible insulation unit

Claim 1

AN INSULATION UNIT ADAPTED TO BE INSTALLED BETWEEN A PAIR OF FRAMING MEMBERS AND A WALL MEMBER FORMING A CONSTRUCTION BAY OPEN ONLY ON ONE END AS VIEWED IN CROSS-SECTION, COMPRISING A PLURALITY OF THIN SHEETS WHICH ARE TO BE MAINTAINED IN FIXED TAUT SPACED RELATIONSHIP AND AT LEAST TWO PAIRS OF FLANGE MEANS TO AFFIX SAID SHEETS IN POSITION FROM THE OPEN END OF SAID BAY; A FIRST OF SAID SHEETS BEING A HEAT REFLECTIVE SHEET TO BE AFFIXED IN SAID BAY OPPOSED TO THE WALL MEMBER, A SECOND OF SAID SHEETS BEING A SUPPORTING SHEET TO BE AFFIXED IN SAID BAY OUTWARDLY OF SAID FIRST SHEET, SAID PAIRS OF FLANGE MEANS BEING FORMED IN PART BY FOLDED ENDS OF THE FIRST AND THE SECOND SHEET AND EXTENDING IN A DIRECTION AWAY FROM SAID WALL AND TOWARDS THE OPEN END OF SAID BAY, A FIST PAIR OF FLANGE MEANS WHICH WHEN AFFIXED ONE TO EACH FRAMING MEMBER IS ADAPTED TO DRAW THE FIRST SHEET TAUT IN A PLANE NORMAL TO SAID FRAMING MEMBERS, S SECOND SHEET TAUT IN SPACED MEANS WHICH WHEN AFFIXED ONE TO EACH FRAMING MEMBER IS ADAPTED TO DRAW AT LEAST THE SECOND SHEET TAUT IN SPACED PLANAR PARALLEL RELATIONSHIP TO SAID FIRST SHEET, SAID PAIRS OF FLANGES BEING SO CONSTRUCTED AND ARRANGED THAT THEY CAN BE AFFIXED TO SAID FRAMING MEMBERS FROM THE OPEN END OF SAID BAY, WHEREBY A CONTINUOUS UNITERRUPTED AIR SPACE OF SUBSTANTIALLY UNIFORM DEPTH IS ESTABLISHED BETWEEN SAID TAUTENED SHEETS EXTENDING FROM ONE FRAMING MEMBER TO THE OTHER.