(57) A selectively collapsible and expandable insulating curtain and the method of making
same, the curtain having a plurality of collapsible tubes, preferably of plastic material,
extending longitudinally for its width and superimposed one on top of the other in
a row in the direction of curtain height. Each tube has an upper wall and a lower
wall secured together by bands of adhering contact on opposite sides of the tubular
cavity. Additional bands of adhering contact secure superimposed tubes to each other
longitudinally along midsections of the upper and lower walls. The side bands of contact
define fold lines allowing collapse and expansion of the tubes as the curtain is raised
and lowered, respectively, in the manner of a venetian blind. The curtain may include
additional rows of superimposed tubes one adjacent to the other in the direction of
curtain thickness. In making the curtain, a plurality of thin-film strips are wound
about the periphery of a forming member with bands of adhering material interlaminated
between adjacent strips, the width of the midsection bands corresponding to the desired
width of the expanded tubes and bands between successive adjoining layers being in
a staggered relationship. After winding is complete, the superimposed strips are cut
transversely, removed from the forming member and straightened to form the curtain.
The number of spaced bands may be such that the strips may also be cut longitudinally
to provide a plurality of curtains. After straightening, means may be secured to the
tubular structure for hanging and selectively collapsing and expanding the curtain.
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