Convertible frictionless to frictional fingertips for a gripper to improve robotic grasp robustness

Patent metadata

Field	Value
Publication number	US-10464218-B2
Application number	US-201816190813-A
Country	US
Kind code	B2
Filing date	Nov 14, 2018
Priority date	May 15, 2016
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

The present invention relates to a gripper system comprising fingers. The gripper fingers are connectable to a gripper arm. The gripper fingers comprise a roller configured to spin around its central axis or a ball element rotatable in any direction; a stopper configured to stop and/or prevent the spinning of the roller or ball. The present invention also relates to a method for grasping and displacing an object.

First claim

The invention claimed is:

1. A gripper finger comprising:
a movable base element connectable to a gripper arm;
a roller configured to spin around its central axis;
a stopper configured to stop and/or prevent the spinning of the roller around its central axis;
wherein the roller is mounted on a rod at its central axis;
wherein said rod is deflectable such that said roller is configured to engage the stopper.

2. The gripper finger according to claim 1 , wherein said finger further comprises an elongated portion extending along an axis perpendicular to the central axis of the roller, with an aperture provided at the bottom of said elongated portion, wherein the rod is mounted such that it passes through said aperture; and
wherein the stopper is connected to said elongated portion at a location distal to said aperture.

3. The gripper finger according to claim 2 , wherein the elongated portion is rotatable around an axis identical or parallel to the roller central axis and wherein the aperture is essentially elongated in the direction of the length of said elongated portion enabling the deflection of the rod.

4. The gripper finger according to claim 3 , wherein the elongated portion is rotatable around an axis parallel to the roller central axis such that there is an offset between the central axis of the roller and the rotation axis of said elongated portion.

5. The gripper finger according to claim 4 , wherein the central axis of the roller is distal to the central rotation axis of the elongated portion rotation.

6. The gripper finger according to claim 5 , wherein the elongated portion is hollow and wherein an elastic element is placed within the hollow portion, wherein the rod is responsive to compression of said elastic element.

7. The gripper finger according to claim 5 , wherein the base element comprises a hollow cylindrical tube extending therefrom;
wherein said finger further comprises a cylindrical portion connected to a proximal portion of the top of the elongated portion and inserted within said hollow cylindrical tube and rotatable therewithin;
wherein said hollow cylindrical tube and said cylindrical portion have a common central axis;
wherein said common central axis is the rotation axis of said elongated portion.

8. The gripper finger according to claim 7 , wherein the elongated portion is hollow and wherein the cylindrical portion comprises a bore extending from the inside of the elongated hollow portion to within said cylindrical portion;
wherein said bore is substantially parallel to the rotation axis of said elongated hollow portion;
wherein the rod is placed within said bore; and
wherein the stopper extends from a distal portion of the bottom of the elongated hollow portion and is substantially parallel to the rotation axis of said elongated hollow portion.

9. A gripper system comprising:
a plurality of arms wherein the proximal ends of each of the arms are at close proximity to each other, wherein each of said arms comprises a mobile member movable thereon;
a motor configured to drive said mobile member;
a control unit;
a plurality of gripper fingers according to claim 1 , each mounted on a corresponding mobile member of said mobile members.

10. A gripper finger comprising:
a ball encasing element;
a ball encased within said ball encasing element wherein a portion of said ball is proximal beyond said ball encasing element proximal side;
wherein said ball is configured move between two modes:
a) a frictionless mode wherein said ball is freely rotatable in any direction;
b) a frictional mode wherein the ball is immobilized;
wherein said gripper finger further comprises:
a hollow receiving cup comprising an opening at its proximal side and a plurality of surfaces within its interior;
a plurality of elastic elements;
wherein the ball encasing element comprises a distal side with a plurality of surfaces and a proximal side in the form of the majority of an external surface of a ball;
wherein said encasing element comprises an aperture within each of said distal side surfaces;
wherein said ball encasing element is placed within the interior of said receiving cup such that each of said ball encasing element distal side surfaces faces a corresponding surface from said hollow receiving cup internal surfaces; and wherein at least one of said plurality of elastic elements is placed between each of said encasing element distal side surfaces and its corresponding hollow receiving cup internal surface that it faces.

11. The gripper finger according to claim 10 , wherein the ball encasing element distal side comprises three surfaces; and wherein the hollow receiving cup comprises three surfaces within its interior;
wherein the ball encasing element distal side three surfaces are orthogonal to one another; and
wherein the hollow receiving cup interior three surfaces are orthogonal to one another.

12. The gripper finger according to claim 10 , wherein a portion of the ball encased within the ball encasing element protrudes the aperture;
wherein each ball encasing element distal surface is displaceable towards its corresponding receiving cup interior surface that it faces, such that the portion of the ball that protrudes the aperture of said ball encasing element distal surface is engageable with said corresponding receiving cup interior surface; and
wherein the ball and the receiving cup interior surface that it is engageable with are constructed such that there is friction upon their engagement.

13. The gripper finger according to claim 10 , wherein the hollow receiving cup internal surfaces are concave spherical surfaces, such that they share a center point with each other and with the ball when said ball is in a resting position.

14. A gripper finger comprising:
a ball encasing element;
a ball encased within said ball encasing element wherein a portion of said ball is proximal beyond said ball encasing element proximal side;
wherein said ball is configured move between two modes:
a) a frictionless mode wherein said ball is freely rotatable in any direction;
b) a frictional mode wherein the ball is immobilized;
a distal base comprising a distal surface and two side arms extending proximally therefrom;
a circumferential ring connected to said distal base two side arms such that said circumferential ring is rotatable around a first axis;
a braking unit comprising:
a) the ball encasing element configured to encase a ball therewithin;
b) the ball encased within said ball encasing element;
c) a stopper unit connected to said ball encasing element such that said ball encasing element is movable in relation to said stopper unit;
wherein said braking unit is connected to said circumferential ring such that said braking unit is rotatable around a second axis.

15. A gripper finger according to claim 14 , wherein the stopper unit comprises a distal portion distal to the ball; wherein said stopper unit distal portion comprises a stopper element extending proximally therefrom; and
wherein said stopper element is configured to engage and immobilize the ball.

16. A gripper finger according to claim 15 , wherein the ball encasing element comprises:
a) an interior round surface in the form of the majority of an outer surface of a ball terminating at a proximal opening;
b) a distal aperture;
wherein a portion of the braking unit ball is proximal to said proximal opening;
wherein said stopper element is configured to pass through said ball encasing element distal aperture.

17. A gripper finger according to claim 14 ,

Assignees

• B G Negev Technologies And Applications Ltd At Ben Gurion Univ
• Technion Res & Dev Foundation
• Technion Res & Dev Foundation

Inventors

• Golan Yoav
• Shapiro Amir
• Rimon Elon

Classifications

• B25J15/103 Primary

  for gripping the object in three contact points · CPC title

• B25J15/0028

  with movable, e.g. pivoting gripping jaw surfaces · CPC title

• B25J15/02

  servo-actuated · CPC title

• B25J15/086

  with means for synchronizing the movements of the fingers · CPC title

• B25J15/106

  moving in parallel relationship · CPC title