Patent ID: 6992900

Claim:
A board unit removably attachable to a board housing frame, comprising: a board body; a panel body for fixedly supporting the board body, the panel body having a stopper insertion hole; an insertion-extraction handle rotatably supported by the panel body having: an operation part, a frame engaging part configured to be engaged with a part of the board housing frame when the operation part is rotated to a specific fixed position and to be disengaged from the board housing frame when the operation part is rotated to a specific release position, and a stopper part configured to be inserted into the stopper insertion hole when the operation part is rotated to the fixed position and to be extracted from the stopper insertion hole when the operation part is rotated to the release position; and a spring unit non-fixedly held either in the stopper insertion hole or on the insertion-extraction handle, the spring unit having a main spring part which, when the stopper part is inserted into the stopper insertion hole, applies a prescribed resistance to the insertion of the stopper part on the insertion-extraction handle, and which, when the stopper part is extracted from the stopper insertion hole, applies a prescribed resistance to the extraction of the stopper part on the insertion-extraction handle.