Bracing for wooden shutters for doors or windows - has transverse bars bolted to shutter timbers to prevent relative displacement of shutters and warping

摘要

All the tongue and groove shutter timbers (1) except the outside ones (1a, 1b) have pairs of trapezoidal shaped grooves (2, 3) cut into them transversely. These receive the side projections (5, 6) of the bar (4). Fixing screws (7) hold the bar to the shutter after bolts (9), passing right through bar and shutter, have been pulled up tight to back washers with bolt nuts. The grip between bars and shutter prevents lateral displacement of the planks with respect to each other and provides a restraint to warping due to changes in atmospheric humidity.