Hello there. I'm new to this forum but found it doing a search trying to research my vintage Wright 1/2 ton hoist. I recently acquired this hoist, and it seems in nice working order. But a cannot figure how to release the arm that locks the the gear / wheel that the lifting chain turns on. I'm sorry I may not use the correct terminology but I'm not real educated on chain hoists. I'm including a couple of photos, two where you can see the locking arm that has an open hole in it. Can anyone tell me what I am missing here? Thanks so much for the help!