End effector with multiple pick-up members

• US 7,390,040 B2
• Filed: 04/22/2003
• Issued: 06/24/2008
• Est. Priority Date: 04/22/2002
• Status: Expired due to Term

• Current Assignee: Milos Misha Subotincic
• Original Assignee: Milos Misha Subotincic
• Inventors: Subotincic, Milos Misha
• Primary Examiner(s): Rodriguez; Saul J.
• Assistant Examiner(s): Lowe; Michael S.
• Application Number:
  US10/420,075
• Publication Number:
  US 20030235491A1
• Time in Patent Office: 1,890 Days
• Field of Search: 294/65, 294/87.1, 294/87.12, 414/225.01, 414/226.01, 414/416.02, 414/627, 414/658, 414/666, 414/667, 414/668, 414/737, 414/749.5, 414/752.1, 414/900, 901/40, 198/468.3
• US Class Current: 294/65
• CPC Class Codes: B25J 15/0052 multiple gripper units or multiple end effectors
• CPC Class Codes: B25J 15/0616 with vacuum
• CPC Class Codes: B65B 35/38 by suction-operated grippers
• CPC Class Codes: B65B 5/08 Packaging groups of articles, the articles being individually gripped or guided for transfer to the containers or receptacles
• CPC Class Codes: B65G 47/91 incorporating pneumatic, e.g. suction, grippers
• CPC Class Codes: B65G 47/918 with at least two picking-up heads
• CPC Class Codes: Y10S 901/40 Vacuum or mangetic

Abstract

An end effector for use with a moving device has a frame and a plurality of operational members mounted for movement on the frame. The effector also has an actuation mechanism directly connected to a first operational member and is operable to move the first operational member from a first position to a second position, and from the second position to the first position. A linking apparatus is provided for linking the first operational member to a second operational member. The actuation mechanism moves the first operational member from the first position to the second position, and results in the second operational member being moved by the linking apparatus from a third position to a fourth position. The operational members can be pick up members for picking up items at one pitch and releasing them at a second pitch.

Claims

1. An end effector for use with a moving device, said end effector comprising:

a) a frame;

b) a plurality of operational members mounted for longitudinal movement on said frame;

c) an actuation mechanism directly connected to a first operational member of said plurality of operational members and operable to move said first operational member from a first position to a second position, and from said second position to said first position;

d) a linking apparatus for linking said first operational member to a second operational member of said plurality of operational members said second operational member not directly connected to said actuation mechanism;

wherein when said actuation mechanism moves said first operational member from said first position to said second position, said second operational member is moved by said linking apparatus from a third position to a fourth position, and when said actuation mechanism moves said first operational member from said second position to said first position, said second operational member is moved from said fourth position to said third position, and wherein said actuation mechanism is directly connected to a third operational member of said plurality of operational members and is operable to move said third operational member from a fifth position to a sixth position, and from said sixth position to said fifth position;

said linking apparatus also for linking said third operational member to a fourth operational member of said plurality of operational members and wherein said actuation mechanism further comprises;

a) a first longitudinally oriented cam block having first and second spaced cam slots in an upper surface of said first cam block each of said first and second slots extending transversely across said upper surface of said first cam block, said first cam block is slidably secured to said frame;

b) a second longitudinally oriented cam block having first and second spaced slots in an upper surface of said second cam block extending transversely across said upper surface of said second cam block, said second cam block being positioned in parallel longitudinal relation to said first cam block and, wherein said second cam block is slidably secured to said frame;

c) a first rod attached to said first cam block and to said first operational member;

d) a second rod attached to said second cam block and said third operational member;

e) a rotary cam comprising of a circular disc, said rotary cam attached to a rotatable shaft and operable to rotate in the same direction as said rotatable shaft; and

f) first and second cam followers protruding from a bottom surface of said rotary cam, wherein a first of said cam followers moves transversely inside a first slot of said first cam block and pushes said first cam block in a first direction, and a second of said cam followers moves transversely inside a first slot of said second cam block and pushes said second cam block in an opposite direction to said first direction;

and wherein said rotatable shaft is driven by a motor associated with said moving device, and a controller is provided for controlling the motor and thus the rotation of said rotatable shaft.

2. An end effector as claimed in claim 1 wherein said linking apparatus is configured such that when said first operational member is at said first position and said second operational member is at said third position, the spacing between said first and second operational members is less than said spacing when said first operational member is at said second position and said second operational member is at said fourth position.

3. An end effector as claimed in claim 2 further comprising a fifth operational member, said fifth operational member not directly connected to said actuation mechanism, said fifth operational member linked by said linking apparatus to said first and second operational members, wherein when said actuation mechanism moves said first operational member from said first position to said second position, said second operational member is moved from a third position to a fourth position, and said fifth operational member is moved from a fifth position to a sixth position, and when said actuation mechanism moves said first operational member from said second position to said first position, said second operational member is moved from said fourth position to said third position, and said fifth operational member is moved from said sixth position to said fifth position.

4. An end effector as claimed in claim 2 wherein said linking apparatus is configured such that when said third operational member is at said fifth position and said fourth operational member is at said seventh position, the spacing between said third and fourth operational members is less than said spacing when said third operational member is at said sixth position and said fourth operational member is at said eighth position.

5. An end effector as claimed in claim 4 wherein when said first, second, third and fourth operational members are in said first, third, fifth and seventh positions respectively, said first, second, third and fourth operational members are equally spaced at a first pitch.

6. An end effector as claimed in claim 5 wherein when said first, second, third and fourth operational members are in said second, fourth, sixth and eighth positions respectively, said first, second, third and fourth operational members are equally spaced at a second pitch.

7. An end effector as claimed in claim 6 wherein said first pitch is greater than said second pitch.

8. An end effector as claimed in claim 4 wherein when said first, second, third and fourth operational members are in said first, third, filth and seventh positions respectively, said first and second operational members are grouped in a first group and said third and fourth operational members are grouped in a second group.

9. An end effector as claimed in claim 8 wherein said operational members of said first group and said operational members of said second group are spaced at a first, equal pitch.

10. An end effector as claimed in claim 4 wherein said actuating mechanism comprises:

a) a first double acting pneumatic cylinder mounted to said frame and said first operational member and a second double acting pneumatic cylinder mounted to said frame and said third operational member;

b) a compressed air source for supplying compressed air to said first pneumatic cylinder and to said second pneumatic cylinder; and

c) a controller for controlling the release of compressed air from said first and second pneumatic cylinders.

11. An end effector as claimed in claim 1 wherein said first, second, third, and fourth operational members are pick up members adapted to pick up and release at least one item.

12. An end effector as claimed in claim 11 further comprising of a vacuum source that is interconnected to provide vacuum to said first, second third and fourth pick-up members, wherein said vacuum source creates a suction force at a suction location on each of said first, second, third and fourth pick-up members, to lift and hold said at least one item.

13. The end effector of claim 12 wherein each of said first, second, third and fourth pick-up members comprises:

a) a pick-up member body;

b) at least one suction cup attached to said body;

each said suction cup interconnected to said vacuum source through at least one passageway.

14. An end effector as claimed in claim 13 wherein said frame comprises at least one hollow pipe having a plurality of openings;

a first opening having a conduit for connection to said vacuum source and second, third, fourth and fifth openings for connection to each of said passageways in said body of said first, second, third and fourth pick up members.

15. An end effector as claimed in claim 14 wherein said frame comprises a pair of hollow pipes fixedly held in longitudinal, parallel relation to each other, each pipe having a rail depending downward from lower surface of said pipes, said first, second, third and fourth pick up members having connectors for connecting to said rails, said connectors permitting said first, second, third and fourth pick up members to move along said rails.

16. An end effector as claimed in claim 14 wherein said pipe has a rail depending from said pipe, said first, second, third and fourth pick up members having connectors for connecting to said rail, said connectors permitting said first, second, third and fourth pick up members to move along said rail.

17. An end effector as claimed in claim 1 wherein said first and second operational members each has a link pin and said linking apparatus comprises a tie link having at least one aperture for engaging said link pins of said first and second operational members.

18. An end effector as claimed in claim 17 wherein said tie link has a first aperture for engaging said link pin of said first operational member, and a second aperture for engaging said link pin of said second operational member, wherein when said actuating device moves said first operational member from said first position to said second position, said link pins of said first and second operational members engage side edges of said apertures, whereby said first operational member pulls said second operational member from said third position to said fourth position.

19. An end effector as claimed in claim 18 wherein when said actuating device moves said first operational member from said second position to said first position, said link pins of said first and second operational members are freely positioned in said apertures, whereby an abutting side of said first operational member abuts a side of said second operational member, and said abutting side of first operational member causes said second operational member to move said operational member from said third position to said fourth position.

20. The end effector of claim 1 wherein said first cam follower moves transversely from said first slot of said first cam block into said second slot of said second cam block to continue to move first cam block in said first direction and said second cam follower moves transversely from said first slot of said second cam block into said second slot of said first cam block to continue to move said second cam block in said opposite second direction.

21. The end effector of claim 20 wherein said rotary cam is also operable to rotate said cam disc in a second rotational direction opposite to said first direction, wherein said first of said cam follower moves transversely inside said second slot of said second cam block and pushes said second cam block in said second direction, and said second of said cam followers moves transversely inside said first slot of said first cam block and pushes said second cam block in said first direction.

22. The end effector of claim 1 wherein said rotary cam is also operable to rotate said cam disc in a second rotational direction opposite to said first direction, wherein said first of said cam follower moves transversely inside said first slot of said first cam block and pushes said first cam block in said second direction, and said second of said cam followers moves transversely inside said first slot of said second cam block and pushes said second cam block in said first direction.

23. The end effector of claim 1 wherein, said fourth operational member not directly connected to said actuation mechanism, and wherein when said actuation mechanism moves said third operational member from said fifth position to said sixth position, said fourth operational member is moved by said linking apparatus from a seventh position to an eighth position, and when said actuation mechanism moves said third operational member from said sixth position to said fifth position, said fourth operational member is moved from said eighth position to said seventh position.

24. An end effector for use with a moving device, said end effector comprising:

a) a frame;

b) a plurality of operational members mounted for movement on said frame;

c) an actuation mechanism directly connected to p first operational member of said plurality of operational members and operable to move said first operational member from a first position to a second position, and from said second position to said first position;

d) a linking apparatus for linking said first operational member to a second operational member of said plurality of operational members said second operational member not directly connected to said actuation mechanism;

wherein when said actuation mechanism moves said first operational member from said first position to said second position, said second operational member is moved by said linking apparatus from a third position to a fourth position, and when said actuation mechanism moves said first operational member from said second position to said first position, said second operational member is moved from said fourth position to said third position;

and wherein said moving device has associated therewith, a rotatable shaft attached to a motor and a controller for controlling the motor; and

wherein said actuation mechanism comprises;

a) a cam block having a first slot in a upper surface of said cam block extending transversely across said upper surface of said cam block, said cam block being slidably secured to said end effector body;

b) a first rod attached to said cam block and secured to at least one of said operational members and extending in a first longitudinal direction;

c) a second rod attached to said cam block and secured to at least another one of said operational members and extending in a second longitudinal direction opposite to said first direction;

d) a rotary cam comprising of a circular disc, said rotary cam attached to said rotatable shaft and rotates in a first rotational direction in the same direction as said rotatable shaft; and

e) a cam follower protruding from bottom surface of said rotary cam, wherein said cam follower moves inside said slot of said first cam block and moves said cam block in one direction when said rotary cam rotates such that said operational members secured to said first and second rods are moved.

25. A robot with a robot arm for moving a plurality of items comprising:

an end effector comprising;

a) a frame having a longitudinally elongated portion;

b) a plurality of operational members mounted to said elongated portion having a direction of longitudinal movement on said elongated portion;

c) an actuation mechanism mounted to said frame and directly connected to a first operational member of said plurality of operational members and operable to move said first operational member longitudinally from a first position to a second position, and from said second position to said first position;

d) a linking apparatus for linking longitudinally said first operational member to a second operational member of said plurality of operational members, said second operational member not directly connected to said actuation mechanism;

said robot further comprising

(i) a connection mechanism proximate a distal end of said robot arm connecting a distal end of said robot arm to said end effector;

(ii) a rotatable shaft extending vertically from said distal end of said robot arm to engage said actuation mechanism of said end effector, said shaft being rotatable about an axis that is generally orthogonal to said direction of longitudinal movement, said shaft co-operating with said actuation mechanism to convert the rotation of said shaft about said axis to operate said actuation mechanism to move said plurality of operational members in said direction of longitudinal movement;

wherein when said actuation mechanism moves said first operational member longitudinally from said first position to said second position, said second operational member is moved longitudinally by said linking apparatus from a third position to a fourth position.

26. A robot as claimed in claim 25 wherein when said actuation mechanism moves said first operational member from said second position to said first position, said second operational member is moved from said fourth position to said third position.

27. A robot as claimed in claim 26 wherein said linking apparatus is configured such that when said first operational member is at said first position and said second operational is at said third position, the spacing between said first and second operational members is less than said spacing when said first operational member is at said second position and said second operational member is at said fourth position.

28. A robot as claimed in claim 26 wherein said linking apparatus is configured such that when said first operational member is at said first position and said second operational member is at said third position, the spacing between said first and second operational members is greater than the spacing when said first operational member is at said second position and said second operational member is at said fourth position.

29. A robot as claimed in claim 25 further comprising a third operational member linked by said linking apparatus to said first and second operational members, said third operational member not directly connected to said actuation mechanism, wherein when said actuation mechanism moves said first operational member from said first position to said second position, said second operational member is moved from a third position to a fourth position, said third operational member is moved from a fifth position to a sixth position.

30. A robot as claimed in claim 29 wherein when said actuation mechanism moves said first operational member from said second position to said first position, said second operational member is moved from said fourth position to said third position, and said third operational member is moved from said sixth position to said fifth position.

31. A robot as claimed in claim 29 wherein said first, second and third operational members are pick up members each adapted to pick up and release at least one item.

32. A robot as claimed in claim 31 further comprising of a vacuum source that is interconnected to said first, second and third pick-up members, wherein said vacuum source creates a suction force at a suction location on each of said first, second and third pick-up members, to lift and hold said at least one item.

33. A robot according to claim 31 wherein each of said first, second and third pick-up members comprises:

a) a pick-up member body; and

b) at least one suction cup attached to said body;

said suction cup interconnected to said vacuum source through at least one passageway in said body.

34. A robot as claimed in claim 33 wherein said frame comprises at least one hollow pipe having a plurality of openings;

a first opening having a conduit for connection to said vacuum source and second, third and fourth openings for connection to each of said passageways in said body of said first, second and third pick up members.

35. A robot as claimed in claim 33 wherein said frame comprises a pair of hollow pipes fixedly help in longitudinal, parallel relation to each other, each pipe having a rail depending downward from lower surface of said pipes, said first, second and third pick up members having connectors for connecting to said rails, said connectors permitting said first, second and third pick up members to move along said rails.

36. A robot as claimed in claim 35 wherein said pipe has a rail depending from said pipe, said first, second and third pick up members having connectors for connecting to said rail, said connectors permitting said first, second and third pick up members to move along said rail.

37. A robin as claimed in claim 25 wherein said first and second operational members each has a link pin and said linking apparatus comprises a tie link having at least one aperture for engaging said link pins of said first and second operational members.

38. A robot as claimed in claim 37 wherein said tie link has a first aperture for engaging said link pin of said first operational member, and a second aperture for engaging said link pin of said second operational member, wherein when said actuating device moves said first operational member from said first position to said second position, said link pins of said first and second operational members engage side edges of said apertures, whereby said first operational member pulls said second operational member from said third position to said fourth position.

39. A robot as claimed in claim 37 wherein when said actuating device moves said first operational member from said second position to said first position, said link pins of said first and second operational members are freely positioned in said apertures, whereby an abutting side of said first operational member abuts a side of said second operational member, and said abutting side of first operational member causes said second operational member to move said operational member from said fourth position to said third position.

40. A robot as claimed in claim 39 wherein said linking apparatus is configured such that when said third operational member is at said fifth position and said fourth operational member is at said seventh position, the spacing between said third and fourth operational members is less than said spacing when said third operational member is at said sixth position and said fourth operational member is at said eighth position.

41. A robot as claimed in claim 39 wherein when said first, second, third and fourth operational members are in said first, third, fifth and seventh positions respectively, said first, second, third and fourth operational members are equally spaced at a first pitch.

42. A robot as claimed in claim 39 wherein when said first, second, third and fourth operational members are in said first, third, fifth and seventh positions respectively, said first and second operational members are grouped in a first group and said third and fourth operational members are grouped in a second group.

43. A robot as claimed in claim 25 wherein said actuation mechanism is directly connected to a third operational member of said plurality of operational members and is operable to move said third operational member from a fifth position to a sixth position, and from said sixth position to said fifth position;

said linking apparatus also for linking said third operational member to a fourth operational member of said plurality of operational members said fourth operational member not directly connected to said actuation mechanism, wherein when said actuation mechanism moves said third operational member from said fifth position to said sixth position, said fourth operational member is moved by said linking apparatus from a seventh position to an eighth position, and when said actuation mechanism moves said third operational member from said sixth position to said fifth position, said fourth operational member is moved from said eighth position to said seventh position.

44. The robot as claimed in claim 25 further comprising a motor for driving the shaft in rotation about said axis, and wherein said apparatus further comprises:

a) a first cam block having first and second cam slots in an upper surface of said first cam block extending transversely across an upper surface of said first cam block, wherein said first cam block is slidably secured to said frame;

b) a second cam block having first and second slots in an upper surface of said second cam block extending transversely across said upper surface of said second cam block, said second cam block being positioned in parallel relation to said first cam block and, wherein said second cam block is slidably secured to said frame;

c) a first rod rigidly attached to said first cam block and to said first operational member;

d) a second rod rigidly attached to said second cam block and said third operational member;

e) a controller associated with the end effector for controlling the motor and the rotation of said rotatable shaft;

f) a rotary cam comprising of a circular disc, said rotary cam attached to said rotatable shaft and operable to rotate in the same direction as said rotatable shaft; and

g) two cam followers protruding from said rotary cam, wherein the first of said cam followers moves inside said slot of said first cam block and pushes said first cam block in one direction, and the second of said cam followers moves inside one slot of said second cam block and pushes said second cam block in the opposite direction.

45. The robot as claimed in claim 25 further comprising a motor for driving the shaft in rotation about said axis, and, wherein said operational members are pick up members and said apparatus further comprising:

a) first and second cam blocks each having one slot formed in the top surface of said cam blocks and extending transversely across upper surface of said cam blocks, each of said first and second cam blocks being slidably mounted to said end effector frame on opposite sides of said frame;

b) a first rod rigidly attached to one side of said first cam block and secured to a first pick-up member;

c) a second rod rigidly attached to one side of said second cam block and secured to a second pick-up member located at a position opposite to said first pick up member on said effector body;

d) a controller for controlling the motor and the rotation of said rotatable shaft;

e) a rotary cam attached to said rotatable shaft and rotates in the same direction as said rotatable shaft; and

f) first and second cam followers protruding from said rotary cam, each for engaging one of said first and second cam blocks, wherein said cam followers move inside said slots of said cam blocks and push said first and second cam blocks in opposite directions when said rotary cam rotates.

46. The robot as claimed in claim 25 wherein said apparatus further comprises:

a) a cam block having one slot formed in the top surface of said cam block and extending transversely across upper surface of said cam block, said cam block being slidably secured to said end effector body;

b) a rod rigidly attached to said cam block and secured to said first operational member;

c) said rotatable shaft attached to said motor;

d) a controller associated with said end effector for controlling the motor and the rotation of said rotatable shaft;

e) a rotary cam attached to said rotatable shaft and rotates in the same direction as said rotatable shaft; and

f) a cam follower protruding from bottom surface of said rotary cam;

wherein when said cam follower is rotated, said cam follower moves inside said slot of said cam block and pushes said block in one direction, said first operational member is moved from said first to said second position.

47. A robot as claimed in claim 25 wherein said first and second operational members are pick up members each adapted to pick up and release at least one item.

48. A robot as claimed in claim 47 further comprising a vacuum source to provide vacuum to said first and second and pick-up members, wherein said vacuum source creates a suction force at a suction location on each of said first and second pick up members, to lift and hold said at least one item.

49. A robot having a robot arm with an end effector, said robot further comprising:

a) a frame having a longitudinally elongated portion;

b) a plurality of operational members mounted for movement in a longitudinal direction to said elongated portion;

c) an actuation mechanism mounted to said frame and directly connected to a first operational member of said plurality of operational members and operable to move said first operational member longitudinally in said longitudinal direction from a first position to a second position, and from said second position to said first position;

d) a linking apparatus for linking longitudinally said first operational member to a second operational member of said plurality of operational members, said second operational member not directly connected to said actuation mechanism;

e) a connection mechanism connecting said robot arm to said end effector;

f) a rotatable shaft extending vertically from said robot arm to engage said actuation mechanism, said shaft being rotatable about an axis that is generally orthogonal to said direction of longitudinal movement;

said actuation mechanism co-operating with said shaft such that said rotation of said shaft about said axis operates said actuation mechanism to move said plurality of operational members in said longitudinal direction;

and wherein when said actuation mechanism moves said first operational member longitudinally from said first position to said second position, said second operational member is moved longitudinally by said linking apparatus from a up and release at least one item.

50. An end effector for use with a moving device, said end effector comprising:

a) a frame,

b) first, second and third operational members mounted in series on said frame for longitudinal movement along said frame,

c) a first and a second link protrusion extending from at least one of first, second and third operational members;

d) a first tie link for linking said first operational member and said second operational member;

e) a second tie link for linking said second operational member and said third operational member;

f) an actuation mechanism directly connected to said first operational member and operable to move with reciprocating movement said first operational member, in a first longitudinal direction from a first position to a second position, and in a second longitudinal direction opposite to said first longitudinal direction, from said second position to said first position, said actuation mechanism not directly connected to said second and third operational members;

wherein said first tie link has at least one longitudinally extending aperture for receiving said first link protrusion extending from one of said first and second operational members,

and wherein said second tie link has at least one longitudinally extending aperture for receiving said second link protrusion extending from one of said second and third operational members

wherein said at least one apertures in each of said first and second tie links is adapted to allow longitudinal reciprocating movement within said at least one aperture, the end effector being operable such that when said actuation mechanism moves said first pick up member from said first position to said second position, said first operational member is moved away from said second operational member and said first link protrusion in said at least one aperture of said first tie link moves in said aperture to an outer edge of said aperture, and

wherein said second operational member is pulled in said first direction by said first tie link and said third operational member is pulled in said first direction by said second tie link, said second link protrusion in said at least one aperture of said second tie link moves in said aperture to an outer edge of said aperture, and wherein the length of said at least one aperture of said first tie link limits the separation of said first operational member from said second operational member, and the length of said at least one aperture of said second tie link limits the separation of said second operational member from said third operational member.

51. An apparatus as claimed in claim 50 further comprising a vacuum source to provide vacuum to said first and second and pick-up members, wherein said vacuum source creates a suction force at a suction location on each of said first and second pick up members, to lift and hold at least one item.

52. The end effector of claim 50 herein said first tie link has at least one aperture for receiving a link protrusion of each of said first and second operational members, and wherein when said actuation mechanism moves said first pick up member from said first position to said second position, said first operational member is moved away from said second operational member and said link protrusion of said first operational member moves in said at least one aperture of said first tie to a first outer edge of said at least one aperture, and said link protrusion of said second operational movement moves in said at least one aperture of said first tie link to a first inner edge of said at least one aperture.

53. The end effector of claim 52 wherein said second tie link has at least one aperture for receiving a link protrusion of each of said second and third operational members, and wherein said second operational member is pulled in said first direction by said first tie link and said third operational member is pulled in said first direction by said second tie link said link protrusion of said second operational member moves in said at least one aperture of said second tie link to an outer edge of said at least one aperture, and said link protrusion of said third operational member moves in said at least one aperture of said second tie link to an inner edge of said at least one aperture of said second tie link.

54. The end effector of claim 50 wherein said first tie link comprises first and second apertures, each of said first and second apertures receiving a link protrusion of said first and second operational members, and wherein said second tie link comprises third and fourth apertures, each of said apertures receiving a link protrusion of said second and third operational members.

55. The end effector of claim 54 wherein an link protrusion of said first operational member is received in said first aperture of said first tie link and a link protrusion of said second operational member is received in said second aperture of said first tie link.

56. The end effector of claim 55 wherein when said actuation mechanism moves said first pick up member from said first position to said second position, and said first operational member is moved away from said second operational member, said first link protrusion moves to an outer edge of said first aperture of said first tie link and second link protrusion moves in said second aperture to an inner edge of said second aperture.

57. The end effector of claim 56 wherein when said actuation mechanism moves said first pick tip member from said second position to said first position, and said first operational member is moved towards said second operational member, said first link protrusion moves to an inner edge of said first aperture of said first tie link, and said second link protrusion moves in said second aperture to an outer edge said second aperture.

58. The end effector of claim 55 wherein when said actuation mechanism moves said first pick up member from said first position to said second position, and said first operational member is moved away from said second operational member, and said second operational member is moved away from said third operational member, a link protrusion of said second operational member moves to an outer edge of said third aperture of said second tie link and a link protrusion of said third operational member moves in said fourth aperture to an inner edge of said fourth aperture of said second tie link.

59. The end effector of claim 50 wherein when said actuation mechanism moves said first operational member from said second position to said first position, said link protrusions of said second and third operational members are freely positioned in said apertures, whereby an abutting portion of said first operation member abuts a portion of said second operation member, and an abutting portion of said second operational member abuts a portion of said third operational member, and said abutting portion of said first operational member causes said second operational member to move in said second direction, and said abutting portion of said second operational member causes said third operational member to move in said second direction.

60. The end effector of claim 59 wherein the convergence of said first, second and third operational members is limited by the abutment of said first, second and third operational members.