Articulated actuated finger with self-locking joints

Patent metadata

Field	Value
Publication number	US-12017346-B2
Application number	US-202117211794-A
Country	US
Kind code	B2
Filing date	Mar 24, 2021
Priority date	Mar 24, 2021
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

An articulated finger. The articulated finger comprises a first phalange; a second phalange; a self-locking joint coupling the first phalange to the second phalange, wherein the self-locking joint is configured to allow motion in a first rotational direction of the first phalange relative to the second phalange and prevent motion in a second rotational direction of the first phalange relative to the second phalange, wherein the first rotational direction is opposite the second rotational direction; and a compliant actuator configured to actuate the first phalange in the first rotational direction relative to the second phalange.

First claim

What is claimed is:

1. An articulated finger comprising:
a first phalange;
a second phalange;
a self-locking joint coupling the first phalange to the second phalange, wherein the self-locking joint is configured to allow motion in a first rotational direction of the first phalange relative to the second phalange and prevent motion in a second rotational direction of the first phalange relative to the second phalange, wherein the first rotational direction is opposite the second rotational direction; and
a compliant actuator configured to actuate the first phalange in the first rotational direction relative to the second phalange; wherein
the ratchet mechanism comprises a ratchet gear coupled to the first phalange; and
a pawl rotatably coupled to the second phalange, wherein the pawl is biased into contact with the ratchet mechanism.

2. The finger of claim 1 , wherein the self-locking joint further comprises an actuator coupled to the pawl, wherein the actuator is configured to bias the pawl out of contact with the ratchet mechanism.

3. The finger of claim 2 , wherein the actuator comprises a shape memory alloy coil.

4. The finger of claim 2 , wherein the self-locking joint further comprises a spring, wherein the spring contacts the pawl and is configured to bias the pawl into contact with the ratchet mechanism.

5. The finger of claim 1 , wherein the compliant actuator comprises a stretchable material.

6. The finger of claim 1 , wherein the compliant actuator comprises a shape memory alloy coil coupled to a line, wherein the shape memory alloy coil is configured to shrink and actuate the first phalange in the first rotational direction relative to the second phalange.

7. A method of assembling an articulated finger with self-locking joints, comprising:
coupling together a distal phalange, a middle phalange, and a first ratchet gear, wherein the first ratchet gear is fixed relative to the distal phalange and is rotatable relative to the middle phalange;
coupling together the middle phalange, a proximal phalange, and a second rachet gear, wherein the second ratchet gear is fixed relative to the proximal phalange and is rotatable relative to the middle phalange;
coupling a first pawl to the middle phalange, wherein the first pawl is configured to engage with the first ratchet gear to establish a first self-locking joint between the distal phalange and the middle phalange; and
coupling a second pawl to the middle phalange, wherein the second pawl is configured to engage with the second ratchet gear to establish a second self-locking joint between the proximate phalange and the middle phalange.

8. The method of claim 7 , further comprising coupling a first end of an actuator to the first pawl, wherein the actuator is configured to rotate the first pawl out of engagement with the first ratchet gear when activated by electric power.

9. The method of claim 8 , further comprising coupling a second end of the actuator to the second pawl, wherein the actuator is configured to rotate the second pawl out of engagement with the second ratchet gear when activated by electric power.

10. The method of claim 7 , further comprising installing a first spring into the middle phalange that biases the first pawl into engagement with the first ratchet gear and installing a second spring into the middle phalange that biases the second pawl into engagement with the second ratchet gear.

11. The method of claim 7 , further comprising coupling threading a line through the proximal phalange and through the middle phalange and coupling a first end of the line to the distal phalange.

12. The method of claim 11 , further comprising coupling a second end of the line to a second actuator that is located off of the articulated finger, wherein when the second actuator is activated by electric power it contracts, pulls on the line, and causes the articulated finger to close.

13. The method of claim 12 , coupling the second actuator to a gripper body and coupling the proximal phalange to the gripper body.

14. A portable multi-finger gripper, comprising:
an electric battery;
a gripper body retaining the electric battery;
a plurality of articulated fingers with self-locking joints each coupled to the gripper body, wherein at least one articulated finger of the plurality of articulated fingers is oriented to close in opposition to the closing direction of at least one other articulated finger of the plurality of articulated fingers, wherein each articulated finger comprises:
a distal phalange;
a middle phalange;
a first ratchet, wherein the first ratchet, a distal end of the middle phalange, and a proximal end of the distal phalange are coupled together to form a first self-locking joint;
a proximal phalange;
a second ratchet, wherein the second ratchet, a proximal end of the middle phalange, and a distal end of the proximal phalange are coupled together to form a second self-locking joint; and
a grip release actuator coupled to the middle phalange, electrically coupled to the electric battery, wherein the grip release actuator is operable to escape the first ratchet and the second ratchet;
and

a plurality of grip close actuators retained by the gripper body, electrically coupled to the electric battery, wherein each grip close actuator is mechanically coupled to one articulated finger and operable to drive the articulated finger to close.

15. The portable multi-finger gripper of claim 14 , further comprising
a grip close control button retained by the gripper body, wherein the grip release actuator is controlled by the grip close control button; and
a grip release control button retained by the gripper body, wherein the grip release actuator is controlled by the grip release control button.

16. The portable multi-finger gripper of claim 14 , wherein the distal phalange, the middle phalange, and the proximal phalange comprise photosensitive resin.

17. The portable multi-finger gripper of claim 14 , wherein each articulated finger further comprises a first pawl, a first spring operable to bias the first pawl into engagement with a first ratchet gear of the first ratchet, a second pawl, and a second spring operable to bias the second pawl into engagement with a second ratchet gear of the second ratchet.

18. The portable multi-finger gripper of claim 17 , wherein a stiffness of the first spring is different from the stiffness of the second spring.

19. The portable multi-finger gripper of claim 14 , wherein each articulated finger further comprises a soft silicone skin over the proximal phalange, the middle phalange, and the distal phalange.

Assignees

• Univ City Hong Kong

Inventors

• Sun Dong
• Hu Qiqiang

Classifications

• B25J9/1085

  positioning by means of shape-memory materials (shape memory actuators F03G7/06) · CPC title

• F03G7/06145

  Springs · CPC title

• B25J15/0009 Primary

  comprising multi-articulated fingers, e.g. resembling a human hand · CPC title

• F16H31/004

  with pawls driven by a rotary cam · CPC title

• B25J9/102

  Gears specially adapted therefor, e.g. reduction gears (gearings in general F16H) · CPC title