The present invention discloses a new type of protective sliding door and, during installation, the positioning mechanism and locking mechanism can be first fixedly installed in a predetermined position, and then the door railing body can be installed, the second connecting piece at the lower part of the pivot connection side of the door railing body can be flexibly connected to the lower part of the positioning mechanism, the connecting piece that can be installed on the first connecting piece can be fixedly assembled with the upper part of the positioning mechanism, so that the installed door railing body can open or close the door by swinging relative to the positioning mechanism and, after the door is closed, the locking mechanism can be connected to the locking side of the door railing body to lock the door railing body.

A novel automatic stall latch device is disclosed. The device is a secure, automatic latch for stall doors that house livestock, but can be retrofitted to any sliding door. The device comprises a locking plate and a wedge that the locking plate slides over to lock the door. A narrow rod is then installed on the side of the sliding door to operate the automatic latch. The locking plate is bolted to the top of the stall or sliding door and operated via the narrow rod that runs down the side of the door. The rod can be actuated to open the stall door. When the door is closed, the locking plate automatically connects to the wedge component that bolts to the top of the stall wall next to the closed door.