The Makerbot has gotten a decent workout this past week, printing legs for Issy and (among other parts) a gripper for an upcoming bot. The third time really is the charm: with all the designs for this gripper and Issy's legs, the third design was the one I stuck with. Here's some pics of the aforementioned HS-55 based grippers I'm creating for a 2011 robowaiter entry:
Each gripper has two printed parts: the HS-55 mount and the C-bracket. The servo mount is the same part for both the left and right sides but I had to slightly tailor the C-brackets to get decent range of motion. Each HS-55 mounts to an AX-12 C-bracket.
The gripper fingers are made of 1/16" thick 5052, about 3/4" wide, mounted with two 2mm screws. Instead of a bearing, I'm using a 3/16" Chicago bolt on the non-driven end of the printed C-bracket. Preliminary tests show the grippers have no problem holding the robowaiter plate.