Welding helmet with eye piece control

• US 3,873,804 A
• Filed: 12/26/1973
• Issued: 03/25/1975
• Est. Priority Date: 04/14/1972
• Status: Expired due to Term

• Current Assignee: Mack Gordon
• Original Assignee: Mack Gordon
• Inventors: Gordon, Mack
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Hairston, Kenneth
• Application Number:
  US05/427,988
• Time in Patent Office: 454 Days
• Field of Search: 219/147 350/150,160,311 2/8
• US Class Current: 219/147
• CPC Class Codes: A61F 9/067 with variable transmission

Abstract

A protective welding lens assembly is shown, as for use in the eye piece of a welding helmet, utilizing a liquid crystal together with an electrical circuit which applies a suitable electrical potential to the liquid crystal to change the same from a uniform light transmitting condition to a uniform approximately opaque condition of very small light transmission solely in response to approach to the welding electrode close to the workpiece to be welded.

Claims

1. A protective welding lens assembly for use with an electrical welding machine having an electrical energizing circuit and having a welding electrode connected thereto by an electrical cable, said assembly being planar and fixedly mounted in a welder'"'"''"'"'s helmet, and comprising a layer of liquid crystal material sandwiched between opposing parallel plates coated over their entire area with unbroken transparent conducting films, said films being pretreated by rubbing the same in parallel lines at right angles to each other whereby to control their polarizing effect upon said liquid crystal material, said plates with the enclosed liquid crystal material being disposed between and parallel to a pair of conventional cross polarizers so arranged that when a suitable electrical potential is established across said conducting films and said liquid crystal layer the lens assembly will change from a uniform light transmitting condition to a uniform high density approximately opaque condition, and means including a low voltage electrical circuit electrically associated with said electrical energizing circuit and responsive solely to approach of said welding electrode to the work to be welded by the wearer of the helmet for applying said suitable electrical potential across said conducting films and said liquid crystal layer in a period of approximately 1/500 of a second.

2. A welding lens assembly as defined in claim 1, wherein said liquid crystal material is of the nematic type of mesophase with a positive dielectric anisotropism.

3. A welding lens assembly as defined in claim 2, wherein said last named means includes a switching device responsive to visible light from a welding arc struck between a welding electrode and a workpiece upon approach of said electrode close to a workpiece.

4. A welding lens assembly as defined in claim 2, wherein said last named means includes a switching device responsive to infra-red rays emitted from an electrode approaching a workpiece prior to the emission of actinic rays.

5. A welding lens assembly as defined in claim 2, wherein said welding machine utilizes direct current, and said last named means includes a current transformer operatively associated with said electrical cable and a switching device in said electrical circuit responsive to current generated in said transformer when said electrode approaches a workpiece.

6. A welding lens assembly as defined in claim 2, wherein said welding machine utilizes alternating current and said last named means includes a capacitance type pickup operatively associated with said electrical cable and a switching device in said electrical circuit responsive to change in said capacitance when said electrode is advanced to a workpiece.

7. A welding lens assembly as defined in claim 2, for use with a welding machine utilizing direct or alternating current, wherein said last named means includes an electromagnetic-responsive ferrite core antenna operatively associated with said electrical cable, and said last named means includes a switching device in said electrical circuit responsive to a signal from said antenna.

8. A welding lens assembly as defined in claim 2, for use with a welding machine having a high frequency welding current, wherein said last named means includes a detector responsive to high frequency, and said last named means includes a switching device in said electrical circuit responsive to a signal from said detector.

9. A welding lens assembly as defined in claim 8, including a switching device in circuit with said high frequency detector, said last named switching device responsive to visible light from a welding arc struck between a welding electrode connected with said welding machine and a workpiece upon approach of said electrode close to said workpiece.

10. A welding lens assembly as defined in clAim 2, wherein said welding machine utilizes alternating current, wherein said last named means includes a voltage transformer operatively associated with said electrical cable and a switching device in said electrical circuit responsive to electrical flow from said transformer when said electrode approaches a workpiece.

11. A welding lens assembly as defined in claim 10, including a switching device in circuit with said first named switching device, said last named switching device responsive to visible light from a welding arc struck between a welding electrode connected with said welding machine and a workpiece upon approach of said electrode close to said workpiece.

12. A welding lens assembly as defined in claim 10, responsive to infra-red rays emitted between a welding electrode and a workpiece upon approach of said electrode close to a workpiece.