Robot arm

• US 6,324,934 B1
• Filed: 03/01/2000
• Issued: 12/04/2001
• Est. Priority Date: 03/01/1999
• Status: Expired due to Fees

• Current Assignee: Creative Design Corp.
• Original Assignee: Creative Design Corp.
• Inventors: Monaghan, Marty
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): HANSEN, COLBY M
• Application Number:
  US09/516,796
• Time in Patent Office: 643 Days
• Field of Search: 744/900.4, 744/901, 414/744.1, 414/744.2, 414/744.5, 901/14, 901/15, 901/21, 901/23, 901/36, 901/17
• US Class Current: 74/490.04
• CPC Class Codes: B25J 19/0029 arranged within the different robot elements
• CPC Class Codes: B25J 9/042 comprising an articulated arm
• CPC Class Codes: B25J 9/104 with cables, chains or ribbons
• CPC Class Codes: Y10T 74/20323 including flaccid drive element

Abstract

A robot arm comprises a first and a second link, the first link having a proximal end and a distal end and the second link having a proximal and a distal end. A fixed pulley, with circumferential surfaces concentric with the first pivot axis is mounted at the proximal end of the first link. A second-link pulley is fixed to the second link for rotation about the second pivot axis. An end effector pulley is fixed to the end effector for rotation about the third pivot axis. A first belt drive is also provided and includes one or more belts connected between the circumferential surfaces of the fixed pulley and the second link pulley so that ratation of the first link relative to the fixed pulley about the first pivot axis causes rotation of the second link about the second pivot axis relative to the first link. One or more idler pulleys is provided and is rotatably mounted to one or both of the links. At least one of the belt drives includes a first belt engaged with the first circumferential surface of an idler pulley and a second belt engaged with the second circumferential surface of the same idler pulley.

Claims

1. A robot arm comprising:

a base;

a first link and a second link, said first link having a proximal end and a distal end, said second link having a proximal end and a distal end;

said proximal end of said first link being pivotally connected to said base for rotation relative thereto about a first pivot axis, said proximal end of said second link being pivotally mounted to said distal end of said first link for rotation relative thereto about a second pivot axis parallel to said first pivot axis;

an end effector pivotally connected to said distal end of said second link for rotation relative thereto about a third pivot axis parallel to said first and second pivot axes,

a fixed pulley rotatably mounted to said base on said first pivot axis defining a circumferential surface concentric with said first pivot axis;

a second-link pulley fixed to said second link for rotation therewith about said second pivot axis, said second-link pulley having a circumferential surface concentric with said second pivot axis;

a housing fixed to said first link defining a circumferential surface concentric with said second pivot axis;

an end effector pulley fixed to said end effector for rotation therewith about said third pivot axis, said end effector pulley having a circumferential surface concentric with said third pivot axis,

a first belt drive including one or more belts connected between said circumferential surfaces of said fixed pulley and said second-link pulley so that upon rotation of said first link relative to said fixed pulley about said first pivot axis, said second link will rotate about said second pivot axis relative to said first link, said first belt drive being arranged to provide a first ratio between rotation of said first link relative to said fixed pulley and rotation of said second link relative to said fixed pulley;

a second belt drive including one or more belts connected between said circumferential surfaces of said housing and said end effector pulley so that upon rotation of said second link relative to said first link about said second pivot axis, said end effector will rotate about said third pivot axis relative to said second link, said second belt drive being arranged to provide a second ratio between rotation of said second link relative to said first link and rotation of said end effector relative to said second link;

one or more idler pulleys rotatably mounted to one or both of said links, each of said idler pulleys defining first and second circumferential surfaces, at least one of said belt drives including a first belt engaged with the first circumferential surface of an idler pulley and a second belt engaged with the second circumferential surface of the same idler pulley.

2. A robot arm as claimed in claim 1 wherein said first ratio is −

2 whereby rotation of said first link through angle θ

causes said second-link pulley and said second link to turn through angle −

2θ

with respect to said first link.

3. A robot arm as claimed in claim 1, wherein said second ratio is −

½

whereby rotation of said second link through angle θ

causes said end-effector pulley and said end-effector to turn through angle −

½

θ

with respect to said second link.

4. A robot arm as claimed in claim 1, wherein said first and second circumferential surfaces of said idler pulley have different diameters.

5. A robot arm of claim 1, wherein said one or more idler pulleys comprises a first-drive idler pulley mounted on said first link, said first belt drive including said first-drive idler pulley.

6. A robot arm as claimed in claim 5, wherein said first belt drive comprises a first belt extending from said circumferential surface of said fixed pulley to said first circumferential surface of said first idler pulley.

7. A robot arm as claimed in claim 6, wherein said first belt drive comprises a second belt extending from said second circumferential surface of said first idler pulley to said second link pulley.

8. A robot arm as claimed in claim 7, wherein said first and second circumferential surfaces of said first idler pulley have a 1:

1 diameter ratio.

9. A robot arm as claimed in claim 1, wherein said one or more idler pulleys include a second-drive idler pulley mounted on said second link.

10. A robot arm as claimed in claim 9, wherein said second belt drive comprises a first belt extending from said circumferential surface of said housing to said first circumferential surface of said second-drive idler pulley.

11. A robot arm as claimed in claim 10, wherein said second belt drive further comprises a second belt extending from said second circumferential surface of said second drive idler pulley to said end effector pulley.

12. A robot arm as claimed in claim 11, wherein the ratio of the diameter of said first circumferential surface of said second-drive idler pulley to the diameter at said second circumferential surface of said second-drive idler pulley is more than 1:

1.

13. The robot arm as claimed in claim 1, wherein said first link and said second link are of equal length.

14. The robot arm as claimed in claim 1, further including elongated components, wherein said second-link pulley includes an internal bore where said elongated components extend from said first link to said second link.

15. The robot arm as claimed in claim 1, further including elongated components, wherein said end effector pulley includes an internal bore where said elongated components extend from said second link to said end effector.

16. The robot arm as claimed in claim 1, further including a first actuator connected to said base for rotation where said rotational driver rotates said first link about said first pivot axis.