The Tiger's turret was redesigned and simplified in July 1943. One of the many improvements was a new locking device to lock the turret in place for travel.
This photo shows the new lock, which was almost identical to that in the Tiger II. It consisted of a wheel attached to the turret, that tightened a ratchet against the gear teeth in the turret ring (which were attached to the hull).
This diagram from the Turret Manual [1, see plate 18] shows how the device worked. The ratchet and the turret's gear teeth are shown at bottom; the turret's armoured wall is at the extreme right.
There was a corresponding hole in the protective cowling of the turret ring.
The lock was fixed to the turret's support ring by 6 bolts. Three of them were part of the ring of bolts that attached the turret's ball-bearing race. This diagram, looking from above, shows that the lock was immediately to the loader's left when he was seated.
This CAD model of the turret base shows the relation of the lock to the turret's gear teeth.
[2] Factory drawing: Turmgehause 2AKF31861U1B11 (overall turret armour)