Hydraulic Parts Retrieval Claw

This is was a project designed and fabricated in about a day to retrieve some parts from the bottom of the three meter experiment when it was full of water.

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Hydraulic claw.

 A flaw in  a part at the bottom of the inner sphere's shaft caused some 3/8" brass pins about 3 inches long to work loose from the experiment.  We needed to remove them, preferably without draining and disassembling the experiment.

The nonmagnetic pins had to be retrieved through a five inch circular port nearly ten feet above the pins' resting location.  There was no line of sight to the pins; they were obscured by the inner sphere.  This claw was attached to a hinged arm on a painters' pole along with an inexpensive submersible camera with CCD monitor that we purchased to inspect the interior of the sphere during the water testing phase.  The spring loaded mechanism on the claw allows it to fold to enter the small diameter access port.  The medical syringe hydraulics (just using water as a hydraulic fluid) allow a strong grip and provide a useful amount of force feedback to let you know you've grasped the object.  This small project saved us from wasting a couple weeks of time on experiment assembly and disassembly, and was used a few times more for retrieival of an instrumented particle (PDF) we introduced into the flow for testing.