A latch pivots about and slides axially on an axle on a second assembly. It is manually pulled axially outward against a spring to clear and pivot over a boss on a first assembly. It then slides over the boss via a boss receiving hole in the latch, interconnecting the two assemblies. A spring urges the latch inward, retaining it on the boss. A hole for a shackle may be provided in the first assembly and in the latch to lock the latch in the connected position. The latch may pivot to a retracted position over a shackle hole in the second assembly to store a lock on the second assembly. It prevents separation of two assemblies that are coupled by a pivoting engagement of one assembly relative to the other.