Tool holders for robotic systems having collision detection

Patent metadata

Field	Value
Publication number	US-11772277-B2
Application number	US-202016860446-A
Country	US
Kind code	B2
Filing date	Apr 28, 2020
Priority date	Jul 26, 2016
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

An example robotic tool holder includes an actuator that is disposed within a housing and configured to hold a tool. The housing and the actuator are in contact via dowels to limit movement of the actuator toward a distal end of the housing. Ones of the dowels that are in contact are in line contact and the ones of the dowels that are in contact are in a triangular geometry. The pressure plate is in line contact with the actuator within the housing around a circumference of the pressure plate. The springs are in contact with the pressure plate to bias the actuator toward a proximal end of the housing via the pressure plate. The springs are in contact with the mounting plate opposite the pressure plate. The sensor switch detects a shock force on the actuator and outputs a signal in response to the shock force.

First claim

What is claimed is:

1. A robotic tool holder, comprising:
a housing having a proximal end and a distal end;
an actuator disposed within the housing and configured to hold a tool, the housing and the actuator being in contact via a plurality of dowels to limit movement of the actuator toward the distal end of the housing, in which two or more of the plurality of dowels are in line contact with each other, and the plurality of dowels are in line contact with the housing or the actuator and in a triangular geometry;
a pressure plate in line contact with the actuator within the housing around a circumference of the pressure plate;
a plurality of springs in contact with the pressure plate to bias the actuator toward the proximal end of the housing via the pressure plate;
a mounting plate to couple the robotic tool holder to a robot, the plurality of springs in contact with the mounting plate opposite the pressure plate; and
a sensor switch to detect a shock force on the actuator and to output a signal in response to detecting the shock force.

2. The robotic tool holder as defined in claim 1 , wherein the actuator is configured to hold a welding torch such that the shock force applied to the welding torch is transferred to the actuator.

3. The robotic tool holder as defined in claim 1 , wherein the actuator and the pressure plate are configured to transfer at least a portion of the shock force to the plurality of springs.

4. The robotic tool holder as defined in claim 1 , where the sensor switch is arranged between the actuator and the housing and in communication with a robot control system configured to control the robotic tool holder to move to a predetermined position in response to the sensor switch signal.

5. The robotic tool holder as defined in claim 1 , wherein the triangular geometry of contacting ones of the dowels is configured to endure acceleration of the robotic tool holder up to at least a selected acceleration without causing the sensor switch to falsely detect the shock force, the triangular geometry including diameters of the dowels and a space between at least two of the dowels in the triangular geometry.

6. The robotic tool holder as defined in claim 1 , wherein the dowels comprise three sets of dowels spaced around an inner circumference of the housing and an outer circumference of the actuator.

7. The robotic tool holder as defined in claim 6 , wherein each of the three sets of the dowels comprises two dowels attached to the housing and one dowel attached to the actuator.

8. The robotic tool holder as defined in claim 6 , wherein each of the three sets of the dowels comprises two dowels attached to the actuator and one dowel attached to the housing.

9. The robotic tool holder as defined in claim 1 , wherein the housing, the actuator, the pressure plate, the mounting plate, and the sensor switch have coaxial interior spaces to permit a cable to traverse through the robotic tool holder to a weld torch coupled to the actuator.

10. The robotic tool holder as defined in claim 1 , wherein the springs exert a spring force on the pressure plate that is greater than a total of a first friction force between the pressure plate and the actuator along the line contact and a second friction force between ones of the dowels attached to the actuator and corresponding ones of the dowels attached to the housing.

11. The robotic tool holder as defined in claim 1 , wherein the dowels comprise two or more sets of dowels spaced around an inner circumference of the housing and an outer circumference of the actuator, each set of dowels comprising two dowels attached to one of the housing or the actuator, and one dowel attached to the other of the housing or the actuator.

12. The robotic tool holder as defined in claim 1 , wherein the dowels comprise Stainless Steel Alloy 416 or titanium.

13. The robotic tool holder as defined in claim 1 , wherein the plurality of springs are die springs, the mounting plate and the pressure plate comprising cavities to retain the plurality of springs.

14. The robotic tool holder as defined in claim 13 , wherein the mounting plate and the pressure plate are configured to retain the plurality of springs parallel to a centerline of the housing.

15. The robotic tool holder as defined in claim 13 , wherein the cavities in the pressure plate are tapered to reduce deflection of the plurality of springs when the pressure plate is tilted within the housing.

16. The robotic tool holder as defined in claim 1 , wherein an end of the actuator that is in line contact with the pressure plate has a curved surface around a circumference of the actuator such that the actuator and the pressure plate form a ball-and-socket-type joint.

17. The robotic tool holder as defined in claim 16 , wherein the line contact changes with respect to the pressure plate when force is transferred by the actuator, and the actuator and the pressure plate are configured to tilt with respect to the housing based on a direction of the shock force.

18. The robotic tool holder as defined in claim 1 , wherein an outer edge of the pressure plate is rounded to permit the pressure plate to rotate within the housing.

19. The robotic tool holder as defined in claim 1 , wherein the dowels comprise three sets of two more aligned dowels in line contact with each other, each set spaced around an outer circumference of the housing and an inner circumference of the actuator.

20. A robotic welding system capable of detecting impacts to a welding torch manipulated by a robot, the robotic welding system comprising:
a robot arm configured to move a welding end of the robot arm;
the welding torch;
a welding torch holder, comprising:
a housing having a proximal end and a distal end;
an actuator disposed within the housing and configured to hold the welding torch, the housing and the actuator being in contact via a plurality of dowels to limit movement of the actuator toward the distal end of the cylindrical housing, in which two or more of the plurality of dowels are in line contact with each other, at least one dowel of the plurality of dowels is in line contact with the housing or the actuator, and the plurality of dowels are arranged in a triangular geometry;
a pressure plate in line contact with the actuator within the housing around a circumference of the pressure plate;
a plurality of springs in contact with the pressure plate to bias the actuator toward the proximal end of the housing via the pressure plate;
a mounting plate to couple the welding torch holder to the robot, the plurality of springs in contact with the mounting plate opposite the pressure plate; and
a sensor switch to detect a shock force on the actuator and to output a signal in response to detecting the shock force; and

a robot controller to receive the signal as an input and, in response to receiving the signal, to control the robot arm to assume a preset position.

Assignees

• Illinois Tool Works

Inventors

• Basit Nauman

Classifications

• B25J13/085 Primary

  Force or torque sensors (B25J13/082, B25J13/084 take precedence) · CPC title

• B23K9/1006 Primary

  Power supply · CPC title

• B23K9/173

  and of a consumable electrode · CPC title

• B23K9/321

  Protecting means · CPC title

• B23K37/006

  Safety devices for welding or cutting · CPC title