Michael S sent over a link to this vintage prisoner transport kit. It's likely there were more than a few of these in use at Arkham Sanitarium by the deputies handling involuntary commitments. Sadly, I've had to settle for using the Chinese-made reproduction cuffs that have flooded the market.
As an aside, I'm delighted to learn there's a blog dedicated to vintage restraints. One of the glories of the internet is how even the smallest niche interest can be shared with the world at large. You may never need to know what kind of handcuffs were in use last century, but when the subject does come up you'll be able to find the answer. That's just insanely cool.