Fixture locating mechanism, abutment joint machinery, feed and discharge machinery, and crystal blank polishing system

The invention discloses a fixture locating mechanism, an abutment joint machinery, a feed and discharge machinery, and a crystal blank polishing system. The fixture locating mechanism comprises a fixture fixing plate which is provided with a groove for sliding a fixture. The fixture fixing plate is provided with a stop locating device on one side of the groove. The stop locating device comprises a stop arm which stretches in or retreats from the sliding path of the fixture under the control of a stop drive structure in order to stop the fixture or allow the fixture to pass through. The fixture fixing plate is provided with a push locating device on the other side of the groove. The push locating device comprises a push arm which stretches in the sliding path of the fixture under the control of a push drive structure in order to push the fixture to move. With the arrangements of the stop locating device and the push locating device, the fixture can be precisely located on the fixture fixing plate. The fixture locating mechanism is simple and reasonable in structure, as well as convenient in maintenance and adjustment.