Abstract: A fabric of amorphous silica is provided having greatly improved life for bag collectors at high temperatures. This is accomplished by applying a thin coating of gold on the amorphous silica fibers of which the fabric is made. The gold is non-reactive at high temperature and has sufficient lubricity to lubricate the fibers and prevent abrasion of adjacent fibers by each other. The gold coating additionally helps protect the amorphous silica fibers from devitrification. An additional coating of indium may also be applied to form a liquid film at high temperature for increased lubrication. The coating may be applied by dipping or spraying the fabric.

Abstract: A protective welding lens assembly for use as the eyepiece of a welding helmet in which the lens assembly can be changed from a light-transmitting condition to an essentially opaque condition of very small light transmission, and vice versa, in response to an electrical signal and wherein the electrical signal for changing the light-transmitting characteristics of the lens assembly is controlled by energy emanating from the mouth of the user of the welding helmet. Preferably, the lens assembly comprises a liquid crystal light shutter; however any lens assembly can be used which can be electrically actuated to change its light-transmitting characteristics. A transducer is disposed within the welding helmet so as to be in front of the mouth of the welder when the helmet is positioned over his face. The transducer can comprise either a microphone responsive to sound from the welder's mouth or a pressure transducer responsive to blowing from the welder's mouth.

Abstract: A control system and method for operating a welding helmet liquid crystal light shutter wherein opening of the liquid crystal light shutter is delayed by two or three seconds after a welding arc is extinguished to permit the welder to apply a welding electrode to the workpiece after the aforesaid two or three seconds to reheat a rapidly-cooling bead. The invention is particularly adapted for use in welding aluminum wherein it is a common practice to place a short weld at the end of a weld head to prevent rapid chilling of the head. In another embodiment of the invention, a liquid crystal light shutter for a welding helmet is caused to open or become transparent quickly; is held open for a few seconds; and is then closed for a few seconds during which latter time the auxiliary welding bead is applied to prevent rapid chilling.

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.