I found this little helve hammer while searching through Google Patents.  The drive and linkage isn't really anything new, but I thought the frame was interesting.  It's all angle iron, and riveted together.  Perhaps a viable alternative for those witout easy access to a welder?  It would be fairly easy to construct and modify.  The idler pulley is also directly attached to the treadle, with no joints or pivoting levers.  It's interesting that the anvil post is made to be easily dismounted in its entirety to be dressed.

 

Here's a link to the patent, from 1926, for the full text.  I recommend downloading the PDF, the scanned and converted text is pretty dire.

 

http://www.google.com/patents/US1685447

This is very close to the linkage that was used in the junkyard hammer build.  If you search Youtube for "Original Junkyard Hammer", you'll find a video.

 

Geoff

Very similar to one I built years ago. The design works! 

Thanks for the link / info. I haven't thought to search patents. I hope to build something by years end.

It's surprisingly easy to make something that'll save you a lot of time, and helve hammers are probably the easiest option. Guided helves are more functional, but require a bit more work. Trawling these old patents is a great source of inspiration (Although how many of them were ever actually built and tested is unclear)

There are a couple patents I've seen that I'm pretty sure (or at least hope) were never built.  This one seems more likely to have been, but it's very small compared to your average Hawkeye, Bradley, Little Giant, etc.  I like the spring arrangement, but I would be concerned about the stock hitting the pitman.  That's less of a conern with a longer helve, but with a little one you'd have to split it like Mofokaye's above.