A structural support located on the bottom section of the door which provides for attachment of the lifting cables on the sectional doors. Also referred to as Bottom Corner Bracket. (Note: Track rollers may have a separate door attachment in some door designs.)
This is the part tha your cranks attach to that allows them to spin freely. A Bottom Bracket Assembly is usually composed of the crank spindle, bearings and bearing cups. All that stuff presses or threads in to the BB Shell which is part of the frame.
The bottom bracket on a bicycle contains an axle to which the crankset is attached and the bearings that allow the axle and cranks to rotate. (The s and pedals are attached to the cranks.) The bottom bracket fits inside the bottom bracket shell, which is part of the bicycle frame.