How to classify the doorsill of ancient buildings in China?

Although the doors and windows of China buildings are movable, they are not directly fixed between columns and beams. There is also a sill member between the movable door and window frame and the load-bearing column beam as an attachment of the door and window frame.

In the sill frame, the horizontal part is the sill, which can be divided into upper sill, middle sill, lower sill and wind sill due to different status; The part standing on the left and right is called the hug frame, which stands very close to the post.

(1) Upper sill: used above the door sash.

(2) Lower sill: used under the door frame, close to the ground.

(3) Middle sill: when the column is high, wood squares are added in the middle, doors are placed under it, and horizontal windows are placed on it.

(4) Wind sill: Use the wind sill under the sill window and stick it on the sill wall couch.