More mystery parts from the bags of LEGO pieces we bought. I can't find a LEGO symbol on it. Is it a LEGO part or some other brand?
This would be a Crane Bucket - Complete Assembly (Top, Jaws, Spring). It could have come from any of 29 sets from 1974 to 2012.
gev has the exact name of the piece, but I'd like to add one more point that could be helpful. When trying to identify pieces as Lego or non-Lego, pay attention to the more obscure standard connections. The small ball above the hinge is a standard small ball joint connection, recently revitalized by the Mixels series (among other things). It connects to the old Lego figure arms, as well as trailer hitches and the like. It's about the only thing on the piece that's standard Lego, but it is a defining feature.
It could've been from the 2012 city mine set. It was used to build the crane.
Here's all the sets this part was in: http://rebrickable.com/parts/3492c01/crane-bucket-complete-assembly-top+-jaws+-spring/14