Patent ID: 8235007

Claim:
A cable release for use in a curtain control system for controlling curtains in a livestock confinement building having an electrically-operated forced air ventilation system and drop curtains, said drop curtains providing supplemental ventilation during power failure or excess temperatures in the livestock confinement building, said curtain control system including a main lifting cable attached to the drop curtains, said lifting cable attached to a winch for lifting the drop curtains into closed position, said curtain control system further including a curtain drop device with a cord release, said cable release comprising: a U-shaped segment of the main lifting cable between a top of the drop curtains and a winch, said U-shaped segment being longer than the linear distance between the top of the drop curtains and the winch; an anchor attached to the U-shaped segment of cable with a latch for holding the U-shaped segment of cable in tension in a hold position; and, a curtain drop device with a cord release, said cord release movable between a hold position for normally holding a latch in hold position by a cord during application of electric current to the curtain drop device and a release position for releasing the latch upon interruption of electric current to the curtain drop device, said latch in release position releasing the anchor with the U-shaped segment of cable, said U-shaped segment of cable having a length sufficient to lower the drop curtains by a preselected amount.