A lock assembly operable to secure a lift linkage associated with moving a boom assembly between a lowered, operative position and a raised, inoperative position is provided. The lock assembly includes a lock pin mounted at a carrying frame interconnected between a lift linkage and the boom assembly. The lock assembly also includes a lock plate mounted at the lift linkage. In the raised position of the lift linkage, the lock plate includes a slot configured to align so as receive the lock pin. Once aligned, the boom is pivoted toward the folded, stowed position. As the boom pivots, the boom pushes the lock pin through the slot. The lift linkage is then lowered to seat the lock pin in the slot and thereby secure the lift linkage and supported boom in the raised, folded position.