Multi-axis articulatable robot having a weld gun with inverted roller screw actuator

• US 6,787,729 B2
• Filed: 10/21/2002
• Issued: 09/07/2004
• Est. Priority Date: 01/23/2001
• Status: Expired due to Term

• Current Assignee: Comau LLC (Stellantis NV)
• Original Assignee: Progressive Tool & Industries, Co. (Stellantis NV)
• Inventors: Kilibarda, Velibor, Dugas, Michael R., Angel, Jeffrey R.
• Primary Examiner(s): Shaw, Clifford C.
• Application Number:
  US10/274,607
• Publication Number:
  US 20030094441A1
• Time in Patent Office: 687 Days
• Field of Search: 219/86.32, 219/86.1, 219/86.25, 219/86.33, 219/86.41, 219/86.51, 219/86.61, 228/44.3, 901/42
• US Class Current: 219/86.32
• CPC Class Codes: B23K 11/31 Electrode holders and actuating devices therefornot restricted to resistance welding or severing by resistance heating B23K37/02
• CPC Class Codes: B23K 11/314 Spot welding guns, e.g. mounted on robots
• CPC Class Codes: B23K 11/315 with one electrode moving on a linear path

Abstract

A multi-axis articulatable robot with a weld gun having a pair of opposing arms, where at least one arm is movable relative to the other arm to apply pressure to a workpiece during a welding operation. At least one of the opposing arms of the weld gun can be rotatable or translatable relative to the other arm. At least one arm is moved relative to the other arm by an inverted roller screw linear actuator. The robot can include an electric controller for controlling the operation of the actuator of the weld gun as an additional axis of the robot movement. The actuator can be mounted on either of the opposing arms.

Claims

1. An apparatus for performing a welding operation on a workpiece comprising:

a robot having an arm with a plurality of axes of movement;

a robot controller for moving the arm along a predetermined path;

a pair of opposing arms, at least one arm movable relative to the opposing arm to apply pressure to the workpiece during a welding operation; and

an inverted roller screw linear actuator for moving the at least one arm relative to the opposing arm in response to the robot controller as an additional axis of movement.

2. The apparatus of claim 1 wherein the inverted roller screw linear actuator further comprises:

an elongate shaft having a first end for connection to one of the opposing arms and a threaded portion opposite from the first end;

a rotatable body having threaded race formed thereon for engaging a plurality of roller bearings interposed between the race and the threaded portion of the elongate shaft to translate the elongate shaft in either linear direction in response to rotation of the body in either rotational direction; and

a rotary motor for rotating the body in either rotational direction.

3. The apparatus of claim 1 wherein the inverted screw linear actuator is mountable to one of the opposing arms.

4. The apparatus of claim 1, wherein the robot controller further comprises:

means for controlling the inverted screw linear actuator.

5. The apparatus of claim 4 wherein the controlling means further comprises:

an electric control system operably engagable with a motor of the inverted roller screw linear actuator to control the motion of an elongate shaft of the inverted roller screw linear actuator.

6. The apparatus of claim 1 wherein the opposing arms are translatable relative to each other.

7. The apparatus of claim 6 wherein the opposing arms form a straight action weld gun.

8. The apparatus of claim 1 wherein the opposing arms are rotatable relative to the other.

9. The apparatus of claim 8 wherein the opposing arms form a pinch type weld gun.

10. The apparatus of claim 1 further comprising:

an interchangeable electrode cap connected to an end of each arm in opposition to one another for movement between an open position spaced from one another to a closed position capturing a workpiece therebetween for welding; and

means for selectively retaining the electrode cap on each arm.

11. An apparatus for performing a welding operation on a workpiece comprising:

a robot having an arm with multiple axes of articulation;

a robot controller for moving the arm along a predetermined path;

a pair of opposing arms, at least one arm movable relative to the opposing arm to apply pressure to the workpiece during a welding operation; and

an inverted roller screw linear actuator for moving the at least one arm relative to the opposing arm and having an elongate shaft with a first end for connection to one of the opposing arms and a threaded portion opposite from the first end, a rotatable body having threaded race formed thereon for engaging a plurality of roller bearings interposed between the race and the threaded portion of the elongate shaft to translate the elongate shaft in either linear direction in response to rotation of the body in either rotational direction, and a rotary motor for rotating the body in either rotational direction in response to the robot controller as an additional axis of articulation.

12. The apparatus of claim 11 wherein the opposing arms are translatable relative to each other.

13. The apparatus of claim 12 wherein the opposing arms form a straight action weld gun.

14. The apparatus of claim 11 wherein the opposing arms are rotatable relative to the other.

15. The apparatus of claim 14 wherein the opposing arms form a pinch type weld gun.

16. The apparatus of claim 11 further comprising:

means for controlling the inverted roller screw linear actuator.

17. The apparatus of claim 16 wherein the controlling means further comprises:

an electric control system operably engagable with a motor of the inverted screw linear actuator to control the motion of an elongate shaft of the inverted screw linear actuator.

18. The apparatus of claim 11 wherein the inverted roller screw linear actuator is mountable to one of the opposing arms.

19. The apparatus of claim 11 further comprising:

an interchangeable electrode cap connected to an end of each arm in opposition to one another for movement between an open position spaced from one another to a closed position capturing a workpiece therebetween for welding; and

means for selectively retaining the electrode cap on each arm.

20. An apparatus for performing a welding operation on a workpiece comprising:

a robot having an arm with multiple axes of movement;

a robot controller for moving the arm along a predetermined path;

a pair of opposing arms, at least one arm movable relative to the opposing arm to apply pressure to the workpiece during a welding operation;

an inverted roller screw linear actuator for moving the at least one arm relative to the opposing arm and having an elongate shaft with a first end for connecting to one of the opposing arms and a threaded portion opposite from the first end, a body having a rotatable threaded race formed thereon for engaging the threaded portion of the elongate shaft to translate the elongate shaft in either linear direction in response to rotation of the body in either rotary direction, and a rotatory motor for rotating the body in either rotary direction; and

an electric control system operably engagable with the rotary motor of the inverted roller screw linear actuator to control the motion of the elongate shaft of the inverted roller screw linear actuator in response to the robot controller as an additional axis of movement.