Impact proof door lock with bolt and tumbler - has blocking abutment rigidly connecting locked bolt to lock case

The lock, esp. on a door, has a bolt mounted in a housing unit or a drop bolt, and a tumbler. In the locking position the bolt, or drop bolt end, is rigidly coupled to the lock case, to prevent lengthways movement inwards, by a blocking abutment brought into operation between lock case and bolt. The abutment may be moved in and out of position by the same movement of the key in turning the block, by means of the key bit. The bolt cannot be moved by heavy blows, impacts or lever action.