Abstract: To provide protection to the sensitive solid ion conductive electrolyte, a metal sleeve is placed to surround the electrolyte, with clearance, and formed with openings having an increasing cross-sectional area starting from the housing or socket towards the bottom of the solid electrolyte tube to provide an approximately even temperature gradient upon exposure of the element to exhaust gases, the sleeve being additionally so formed that deflection surfaces or vanes are formed internally thereof, for example by punching the openings through the sleeve as elongated slots leaving deflecting vanes, to deflect gases passing through the openings from direct impingement on the solid electrolyte tube to protect the solid electrolyte tube against impact and contamination.

Abstract: A thermal change-over switch has a switch arm movable between first and second contact positions with an intervening dead center position, a temperature responsive bimetal element is connected to the switch arm through a prestressed resilient element so as to effect quick switch-over of the arm from either position to the other while maintaining contact pressure up to the time of switch-over.