Abstract: A flexible drive coupling for power transmission shafts having coupling elements of plastic material containing improved metal elements therein to form strengthened locking means for securing the coupling elements on the coupled transmission shafts.

Abstract: An improved plug valve has means for operating a stem and plug assembly therein, including a sleeve secured within an opening in a valve cover plate, and a tubular gland which is threadably engaged in the sleeve and which coacts with upper and lower stop means incorporated into the stem to raise and lower the plug. Annular sealing rings are employed between the valve stem and the gland and between the gland and the sleeve to prevent leakage, especially when the plug is in a raised position. The upper end of the gland is shaped to receive means for turning the gland to thereby raise or lower the valve stem and plug assembly. A lock nut is rotatable about the gland and selectively against the upper end of the sleeve, whereby the gland may be tightly secured in the sleeve to thereby hold the plug in a sealing position within the valve bore.