Wrist actuator

• US 4,729,253 A
• Filed: 08/20/1986
• Issued: 03/08/1988
• Est. Priority Date: 01/21/1986
• Status: Expired due to Term

• Current Assignee: Agility Robotics Inc.
• Original Assignee: Mark E. Rosheim
• Inventors: Rosheim, Mark E.
• Primary Examiner(s): Herrmann, Allan D.
• Application Number:
  US06/898,301
• Time in Patent Office: 566 Days
• Field of Search: 74/5.41, 74/5.47, 74/98, 74/479, 248/179, 464/109, 464/125, 901/25, 901/28, 901/29
• US Class Current: 74/490.06
• CPC Class Codes: B25J 17/0275 Universal joints, e.g. Hooke, Cardan, ball joints
• CPC Class Codes: B25J 17/0283 Three-dimensional joints
• CPC Class Codes: B25J 9/104 with cables, chains or ribbons
• CPC Class Codes: Y10T 74/1888 Geared connections
• CPC Class Codes: Y10T 74/20335 Wrist

Abstract

The present invention includes a robot wrist actuator having a cylindrical housing with first and second housing wall portions coaxially disposed with respect to each other. First and second gimbal assemblies are included within the housing for pitch and yaw movement and are rotatably mounted to the housing. First and second linkages connect the first and second gimbal assemblies such that movement is transmitted from one gimbal assembly to another.

Claims

1. A mechanical joint comprising:

a housing structure rotatable about a first axis;

first and second gimbal assemblies pivotally attached to the housing structure and each gimbal assembly having an articulation point along the first axis when the joint is in a first position; and

first and second linkage means for transmitting selective movement from the first gimbal assembly to the second gimbal assembly such that the second gimbal assembly is movable in a selected sequence.

2. The mechanical joint of claim 1 and wherein each gimbal assembly comprises:

a shaft rotatably mounted to the housing structure and disposed perpendicularly to the first axis;

bail means for transmitting motion to a bail means of the other gimbal assembly, the bail means being rotatably mounted within the housing means; and

a clevis assembly having a passage through which the bail means extends, the clevis assembly being pivotally attached to the shaft, the shaft having means for transmitting rotational movement to another shaft of the other gimbal assembly such that rotational movement of one shaft is transmitted to the other shaft and rotational movement of one bail is transmitted to the other bail.

3. The joint of claim 2 wherein each bail has two ends and each end has a gear end portion for transmitting rotational movement from one bail to the other bail.

4. The joint of claim 2 wherein the means for transmitting rotational movement from one shaft to the other is a gear shaft portion.

5. The joint of claim 2 and further including bearing means disposed on opposing sides of the bail means within the passage of the clevis assembly, slidably connecting the bail means with the clevis assembly.

6. The joint of claim 2 and further including drive means having means for supplying rotational motion to the bail means of the first gimbal assembly, means for supplying rotational motion to the shaft of the first gimbal assembly and means for supplying rotational motion to the first gimbal assembly about the first axis.

7. A mechanical joint comprising:

housing means having first and second housing wall portions coaxially disposed with respect to each other along a first axis;

bearing means retaining the housing portions relative to each other and permitting relative rotational movement of the housing wall portions;

first and second gimbal assemblies pivotally attached to the housing means and each gimbal assembly having a center point on the first axis when the joint is in a first position; and

first and second linkage means movably connecting the first and second gimbal assemblies for transmitting movement between the first and second gimbal assemblies such that the gimbal assemblies are movable angularly between the first position and a second position and wherein the first and second gimbal assemblies are rotatable about the first axis through movement of the first housing wall portion with respect to the second housing wall portion.

8. The mechanical joint of claim 7 and wherein each gimbal assembly comprises:

a shaft rotatably mounted to the housing means and disposed perpendicularly to the first axis;

bail means for transmitting motion to a bail means of the other gimbal assembly, the bail means being rotatably mounted within the housing means; and

a clevis assembly having a passage through which the bail means extends, the clevis assembly being pivotally attached to the shaft, the shaft having means for transmitting rotational movement to another shaft of the other gimbal assembly such that rotational movement of one shaft is transmitted to the other shaft and rotational movement of one bail is transmitted to the other bail.

9. The joint of claim 8 wherein each bail has two ends and each end has a gear end portion for transmitting rotational movement from one bail to the other bail.

10. The joint of claim 8 wherein the means for transmitting rotational movement from one shaft to the other is a gear shaft portion.

11. The joint of claim 8 and further including bearing means disposed on opposing sides of the bail means within the passage of the clevis assembly, slidably connecting the bail means with the clevis assembly.

12. The joint of claim 8 wherein each shaft of each gimbal assembly extends through a slot in the first housing wall portion and is rotatably connected to the second housing wall portion.

13. The joint of claim 8 and further including drive means having means for supplying rotational motion to the bail means of the first gimbal assembly, means for supplying rotational motion to the shaft of the first gimbal assembly and means for supplying rotational motion to the first gimbal assembly about the first axis.

14. The joint of claim 13 wherein the means for supplying rotational motion to the bail is a first rod member pivotally attached to the bail of the first gimbal assembly, wherein the means for supplying rotational motion to the shaft of the first gimbal assembly is a second rod member pivotally attached to the shaft of the first gimbal assembly and wherein the means for supplying rotational motion to the first gimbal assembly includes a third rod member attached to the first gimbal assembly for transmission of rotational motion to the first gimbal assembly.

15. The joint of claim 14 wherein the drive means further includes first and second sleeves disposed coaxially about the third rod member and in sliding relationship with respect to the third rod member along the first axis with the first rod member being pivotally attached to the first sleeve and the second rod member being pivotally attached to the second sleeve such that when either the first or second sleeve is moved along the first axis, either the first or second rod member is movable independently of each other and independently of the third rod member.

16. The joint of claim 14 wherein the drive means further includes first, second and third electric motors for actuating the first, second and third rod members, respectively.

17. A drive mechanism for providing motive force to a mechanical joint having first and second gimbal assemblies, each gimbal assembly having means for moving the gimbal assembly about a pitch axis, means for moving the gimbal assembly about a yaw axis, and means for permitting the gimbal assembly to rotate about a first axis, the drive mechanism comprising:

a first rod member pivotally attached to the first gimbal assembly for providing motive force to the first gimbal assembly for movement about the pitch axis;

a second rod member pivotally attached to the first gimbal assembly for providing motive force to the first gimbal assembly for movement about the yaw axis; and

a third rod member attached to the first gimbal assembly or providing rotational motive force to the first and second gimbal assembly.

18. The joint of claim 17 wherein the first means for supplying motive force includes a first sleeve disposed coaxially about the third rod member and wherein the second means for providing motive force includes a second sleeve coaxially disposed about the third rod member, both first and second sleeves disposed along the first axis with the first rod member being pivotally attached to the first sleeve and the second rod member being pivotally attached to the second sleeve such that the first, second, and third rod members are movable independently of each other without interference.

19. The joint of claim 17 wherein the first means for providing motive force is a first electric motor, and the second means for providing motive force is a second electric motor.