They could be chain holders, but I don't think they are. If you look at the spring setup they're holding the tool open, the opposite of what you'd want a chain holder to do. But it's also opposite of how the hooks would seem to function.
Pignons being gears makes me wonder if maybe they're wear checkers for block chain? or maybe a quick guage for a chain ring width or overall width of a double chainwheel assembly ?
Playing around with some photo software, it looks like the dimension between the insides of the hooks when fully closed would be about 1 inch, and the tips take up about 5/16 altogether, so a chain wear checker for 1" pitch seems possible. Or maybe it can check wear of both the chain and/or the chainring?
Anyone know who A. cholain was or what they specialized in making?
Steve Birmingham Lowell, Massachusetts USA
Message: 8 Date: Sat, 17 Oct 2009 16:45:22 -0400 From: <Stronglight49@aol.com> Subject: Re: [CR] What are these tools? Could they be for holding a chain still mounted on a bike under tension while adding or removing a link to a section which would be held in the open center of the tool? I assume the "hooks" at the bottom of the open space could prevent the chain from slipping off of the tool.
VAR made an effective chain holder tool [VAR #424 "Monte-chaines"] for similar purpose. Handy when installing a separate link... you don't need to wrestle with chain tension to make the chain slack while attaching a new outer plate.
BOB HANSON, ALBUQUERQUE, NEW MEXICO, USA