Door structure

Claim 2

A damage-minimizing door comprising: a flexible curtain having an upper end and a lower end and side edges; a curtain winding mechanism; said upper end of said curtain being secured to said winding mechanism for moving said curtain upwards and downwards; a pair of parallel spaced apart guide channels, said side edges of said curtain being movable in said guide channels, being sealingly engageable therewith under at least atmospheric pressure and being releasable therefrom at a predetermined impact force on said curtain; and, a rigid bar secured adjacent the lower end of said curtain, said rigid bar being releasably secured to said curtain and releasing therefrom at said predetermined impact force.

Claim 3

A damage-minimizing door as claimed in claim 1 wherein said flexible curtain is of hard rubber.

Claim 4

A damage-minimizing door as claimed in claim 1 wherein said curtain winding mechanism includes a winding drum, motor means for actuating said winding drum, and a pair of torsion springs provided at the ends of said drum.

Claim 5

A damage-minimizing door as claimed in claim 1 wherein said flexible curtain includes sealing means extending along said side edges of said curtain.

Claim 6

A damage-minimizing door as claimed in claim 1 wherein said bar is pressurably secured to said curtain.

Claim 7

A damage-minimizing door as claimed in claim 1 wherein said flexible curtain is compressible and includes a thicker area along each edge thereof engageable with said guide channels; said guide channels including means for restraining movement of said curtain laterally out of said guide channels.

Claim 8

A damage-minimizing door as claimed in claim 6 wherein said restraining means comprises roller means engageable with an inner side surface of said thickened areas.

Claim 9

A damage-minimizing door as claimed in claim: 6 wherein said restraining means includes projections extending into a channel defined by said guide channels to provide a throat of reduced dimension relative to said thickened area of said curtain to restrain lateral movement of said curtain.

Claim 10

A door as claimed in claim 1 wherein said guide channels each include an upper portion movable from a closed channel position to an open channel position to provide access to said guide channels.

Claim 11

A damage-minimizing door including: a flexible curtain having a first upper end, a second lower end and side edges; a curtain winding mechanism, said first end of said curtain being secured to said curtain winding mechanism for moving said curtain upwards and downwards to respectively open and close a doorway; a pair of parallel and spaced apart guide channel means each comprising an elongate slot whose mouth faces into said doorway, said side edges being movable upwardly and downwardly in said slot as said curtain is respectively moved up and down; said side edges sealingly engaging said channel means when said door is employed in an environment which is at least at atmospheric pressure to normally restrain lateral movement of said side edges through the slot mouth from said guide channel means; and, said side edges of said flexible curtain being pulled laterally through the slot mouth from said guide channel means when a predetermined impact force is applied to said flexible curtain, causing at the most, negligible damage to said guide channel means and minimal damage to said flexible curtain.

Claim 12

A damage-minimizing door including: a flexible curtain having a first upper end, a second lower end and side edges; a curtain winding mechanism, said first end of said curtain being secured to said curtain winding mechanism for moving said curtain upwards and downwards to respectively open and close a doorway; a pair of parallel and spaced apart guide channel means each comprising an elongate slot whose mouth faces into said doorway, said side edges being movable upwardly and downwardly in said slot as said curtain is respectively moved up and down; said side edges sealingly engaging said channel means when said door is employed in an environment which is at least at atmospheric pressure to normally restrain lateral movement of said side edges through the slot mouth from said guide channel means; and, said side edges of said flexible curtain being pulled laterally through the slot mouth from said guide channel means when a predetermined impact force is applied to said flexible curtain, causing at the most, negligible damage to said guide channel means and minimal damage to said flexible curtain.

Claim 13

A damage-minimizing door as claimed in claim 10 wherein said curtain incudes a compressible thicker area along each edge thereof engageable with said guide channels; said guide channels including, adjacent said slot mouth, restraining means for restraining movement of said curtain laterally out of said guide channel means.

Claim 14

A damage-minimizing door as claimed in claim 11 wherein said restraining means includes projections extending into said channel means to define a throat of reduced dimension relative to said thickened area of said curtain to restrain lateral movement of said curtain.

Claim 15

A damage-minimizing door as claimed in claim 11 wherein said guide channel means each include an upper portion movable from a closed channel position to an open channel position to provide access to said guide channel means.

Claim 16

A damage minimizing door as claimed in claim 11 further including a rigid bar releasibly attached to the second lower end of said curtain and releasing therefrom at said predetermined impact force.