US 9,808,936 B2
Two-phase gripper to reorient and grasp
Nikhil Narsingh Chavan Dafle, Cambridge, MA (US); Alberto Rodriguez Garcia, Medford, MA (US); and Matthew T. Mason, Pittsburgh, PA (US)
Assigned to Massachusetts Institute of Technology, Cambridge, MA (US); and Carnegie Mellon University, Pittsburgh, PA (US)
Filed by Massachusetts Institute of Technology, Cambridge, MA (US)
Filed on Jul. 1, 2016, as Appl. No. 15/200,110.
Claims priority of provisional application 62/200,283, filed on Aug. 3, 2015.
Prior Publication US 2017/0036354 A1, Feb. 9, 2017
Int. Cl. B25J 15/00 (2006.01); B25J 15/12 (2006.01); B25J 15/02 (2006.01)
CPC B25J 15/0004 (2013.01) [B25J 15/0042 (2013.01); B25J 15/0253 (2013.01); B25J 15/12 (2013.01); Y10S 294/902 (2013.01)] 4 Claims
OG exemplary drawing
 
1. Two-phase gripper to reorient and grasp an object while being picked up comprising:
a parallel jaw gripper including a pair of opposed, two-phase fingers, each finger including a cavity covered by an elastic strip, the elastic strip including a point contact providing minimal frictional resistance to rotation of the object and wherein the elastic strip has a stiffness, K, such that Fpivot/2δpivot≤K≤Fgrasp/2δgrasp wherein δpivot is maximum allowable deflection for a first relatively lower force Fpivot suitable for pivoting; and wherein δgrasp is minimum extension of the elastic strip to recede into the cavity for a second relatively higher force;
whereby closure of the jaws of the gripper on the object at the first relatively lower force results in contact with lower friction between the point contact on the elastic strip and on the fingers and the object allowing the object to rotate under gravity as the gripper is raised; and
whereby closure of the jaws of the gripper on the object at the second relatively higher force causes the elastic strip to recede into the cavity resulting in multi-point contact with higher friction between the fingers and the object to securely grasp the object.