A prevent out locking device that is used for single arm -drag car carriage back door

The utility model provides a prevent out locking device that is used for single arm -drag car carriage back door, belong to carriage railway carriage or compartment door locking device technical field, including last latch hook, lower latch hook, the locking hydro -cylinder, go up the locating part, lower locating part, go up fitting pin and lower fitting pin, it is the member that one end has the crotch with lower latch hook to go up the latch hook, the middle part of going up latch hook and lower latch hook hinges the lower part in box one side, it lies in the top of latch hook down to go up the latch hook, the piston rod of locking hydro -cylinder and the one end that last latch hook does not have the crotch are articulated, the cylinder body of locking cylinder is articulated with the one end that lower latch hook does not have the crotch, it fixes on the back door with lower fitting pin to go up the fitting pin, the one end of hook strip crotch of locking articulates on last fitting pin, the one end of locking the hook strip crotch down articulates under on the fitting pin, a lower locating part is all fixed on the box for limiting go up latch hook rotation angle's last locating part and be used for restriction latch hook rotation angle down. The utility model discloses the locking hydro -cylinder is direct to link to each other with upper and lower latch hook, need not link mechanism, simple structure, convenient operation.