John Deere uses 'bear claws' on all their cabs from the 4440 tractors up to 8000 series. They are not lockable internally in the latch--the latch button on the tractor has a lock cylinder in it which prevents the button from being pushed in when the lock is engaged.

Thanks for the tip MARTINSR, I may do this one myself.

Remember 9-11-01--God Bless the USA
JUSTICE, not REVENGE, will prevail

1951 Chevy 1/2-ton Pickup truck