WELDER WITH INDIRECT SENSING OF WELD FASTENER POSITION

• US 20170239747A1
• Filed: 09/18/2014
• Published: 08/24/2017
• Est. Priority Date: 09/18/2014
• Status: Active Grant

• Current Assignee: Doben Limited
• Original Assignee: Doben Limited
• Inventors: Koscielski, Larry, Britton, Simon, Branoff, Matt
• Granted Patent: US 10,092,973 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 11/0053 Stud welding, i.e. resistive with an arc B23K9/20
• CPC Class Codes: B23K 11/253 the measured parameter being a displacement or a position
• CPC Class Codes: B23K 11/315 with one electrode moving on a linear path

Abstract

An upper electrode assembly for welding fasteners includes a body that supports an electrode that has an aperture. The aperture is configured to receive a movable pin of a lower electrode assembly arranged opposite the upper electrode assembly. The lower electrode assembly supports a fastener in a welding position. The upper electrode assembly includes a position sensor which includes a position sensor member that is arranged in the body and is configured to cooperate with the pin to detect a fastener welding characteristic.

Claims

1. An upper electrode assembly for welding fasteners, wherein the upper electrode assembly includes a body supporting an electrode having an aperture, the aperture is configured to receive a movable pin of a lower electrode assembly arranged opposite the upper electrode assembly, the lower electrode assembly supports a fastener in a welding position, the upper electrode assembly comprising:

a position sensor including a position sensor member arranged in the body and configured to cooperate with the pin to detect a fastener welding characteristic.

2. The electrode assembly according to claim 1, wherein the position sensor has a linear variable displacement transducer (LVDT).

3. The electrode assembly according to claim 2, wherein the body includes a bore, and the position sensor includes a piston slidably received in the bore, the LVDT having a LVDT core secured to one side of the piston.

4. The electrode assembly according to claim 3, wherein the position sensor member includes a probe slidably received in the aperture and secured to another side of the piston opposite the LVDT.

5. The electrode assembly according to claim 4, wherein the probe includes a removable tip on a side opposite the piston, the tip configured to engage the pin.

6. The electrode assembly according to claim 3, comprising an air port provided in the body and in fluid communication with an air source and the piston.

7. The electrode assembly according to claim 1, comprising a water jacket surrounding at least a portion of the body and in fluid communication with a fluid cooling source.

8. A weld gun assembly including first and second electrode assemblies, the first electrode configured to support a workpiece to which a fastener is welded, the weld gun assembly comprising:

the first electrode assembly includes a movable pin configured to support the fastener in a welding position; and

a second electrode assembly includes a body supporting an electrode having an aperture, the aperture is configured to receive the movable pin, the second electrode assembly has a position sensor member arranged in the body and configured to cooperate with the pin to detect a fastener welding characteristic.

9. The weld gun assembly according to claim 8, wherein the first electrode assembly includes a lower electrode having a surface configured to support the workpiece, with the pin protruding through the workpiece.

10. The weld gun assembly according to claim 9, wherein the pin is movable between multiple positions corresponding to the fastener welding characteristic, the position sensor member moving with the pin.

11. The weld gun assembly according to claim 8, wherein a position sensor includes the position sensor member, the position sensor has a linear variable displacement transducer (LVDT).

12. The weld gun assembly according to claim 11, wherein the body includes a bore, and the position sensor includes a piston slidably received in the bore, the LVDT having an LVDT core secured to one side of the piston.

13. The weld gun assembly according to claim 12, wherein the position sensor member includes a probe slidably received in the aperture and secured to another side of the piston opposite the LVDT.

14. The weld gun assembly according to claim 13, wherein the probe includes a removable tip on a side opposite the piston, the tip configured to engage the pin.

15. The weld gun assembly according to claim 12, comprising an air port provided in the body and in fluid communication with an air source and the piston.

16. The weld gun assembly according to claim 8, comprising a water jacket surrounding at least a portion of the body and in fluid communication with a fluid cooling source.

17. The weld gun assembly according to claim 8, including a position sensor that includes a position sensor member, the position sensor includes a position sensing element in communication with the position sensor member, the position sensing element arranged outside the body.

18. A method of detecting a fastener welding characteristic during welding, the method comprising the steps of:

supporting a fastener with a movable pin at one electrode assembly;

clamping the fastener to a workpiece with the one electrode assembly and another electrode assembly; and

engaging the movable pin with a position sensor member during the clamping step to detect a fastener welding characteristic.

19. The method according to claim 18, wherein the clamping step includes receiving the movable pin within an electrode of the other electrode assembly.

20. The method according to claim 18, wherein a position sensor includes the position sensor member and has a linear variable displacement transducer (LVDT), and the engaging step includes axially displacing the LVDT.

21. The method according to claim 20, wherein the position sensor member includes a probe operatively secured to the LVDT, and the engaging step includes the probe engaging the movable pin.