I do not know what they are called, but they are the cranks that came with Hercules bicycles. Some of them had the H chainwheels, while others had the full name "HERCULES" cut into the chainwheel.

silvercreek, as far as locating them, there was a set on eBay recently but they didn't sell and they were never relisted. While I think they're nice looking cranks, I think they'd stand out like a sore thumb on your Raleigh. In a strange turn though, my 1964 Hercules cruiser has a Raleigh heron chainring as can be seen in the third picture!


Hercules Chainring by Sallad Rialb, on Flickr


Hercules Roadster - 1946 - 3 by Sallad Rialb, on Flickr


Hercules Cruiser - 1964 - 1 by Sallad Rialb, on Flickr