Unique set of old clamps

[stav]

I was at the Reninger's flea market over the weekend and I came across a unique set of hand screw type clamps. They wanted $150 each so I figured it was best that I not touch them though. The design had a gear mechanism rather than the traditional twin screws. I've never seen anything like them and thought I'd share them here as there might be some interest in them. They are labeled as Black Brothers clamps.

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I found this site that shows the patent information about them. http://zengrain.com/black-brothers-patent-clamp/

Looks like a neat design, guessing cost killed them.

[Admiral]

Interesting. I've never come across these in the wild (or at tool swaps either).

[Timberwolf]

Interesting.  I've never come across these in the wild (or at tool swaps either).

......................
Same here...and I have seen a gazillion clamps...unique design but expensive to manufacture.

[AHill]

Looks like a clamp made specifically for some type of manufacturing process. The curved blocks may have been added to alter the original clamping profile.

[Admiral]

Looks like a clamp made specifically for some type of manufacturing process.  The curved blocks may have been added to alter the original clamping profile.

I don't think so, when I googled around yesterday, they were generally sold as part of their product line; saw the patent as well and it's made as designed.  Again, interesting clamp; and I agree with Jack, they would have been expensive to manufacture, and perhaps were the Crucible Tools "Lump Hammer" of the period (I mean, $130 for a 2 lb hammer??) and they didn't sell many sets.

[Stwood_]

Interesting clamps for sure.