Locking device for a livestock head gate

An improved livestock head gate comprising:

• two doors equipped with respective roller carriages at upper ends thereof;
• an overhead guide shaft traversing across an animal-receiving opening of the head gate and on which the respective roller carriages are rollingly engaged for rolling movement of said two doors toward one another into a closed position bracing a livestock animal between said doors and away from one another into an open position releasing said livestock animal from between said doors;
• each roller carriage comprising a respective locking device that comprises:
• a primary shaft-receiving member having a first through-hole therein through which the overhead guide shaft passes;
• a spring-receipt member fixed to the primary shaft-receiving member and projecting outwardly therefrom in a direction along said upright support shaft;
• a locking spring acting against said spring-receipt member in a manner biasing the primary shaft-receiving member toward a tilted locking position;
• and
• a secondary movable locking member retained beside the primary shaft-receiving member in a manner tiltable together therewith and displaceable relative thereto in a direction upwardly and downwardly therealong, said secondary movable locking member having a second through-hole therein through which the overhead guide shaft also passes and which is dimensioned to place a perimeter edge of the second through-hole into biting engagement with the periphery of the overhead guide shaft in the tilted locking position.