Abstract: A cow-milking parlor includes an elongate milking pit, and a plurality of head locks or restraining devices which are arranged in a row paralleling the pit's long axis. The head locks cooperate with an elevated bar extending along the pit to confine the cows at an oblique angle with respect to the pit axis. Each head lock includes an upright fixed-position bar and an upright locking bar having a locking portion which is shiftable relative to the fixed-position bar, toward and away from a restraining position. The plural head locks are actuated coordinately by a gang rod connecting the locking bars to a suitable driving mechanism.