Abstract: The present disclosure is related to an improved pivotal positioning member for use as a joining knuckle of a shade, and particularly for a large beach umbrella. The pivotal positioning member includes an upper element and a lower element pivotally joined by a pin. The upper element is provided with a projection block on each side thereof which is slidably engaged with an arcuate groove defined on the top edge of each upright lug of the lower element; and at the bottom end of the upper element is disposed a number of positioning grooves which will be in selective engagement with the front end of a spring-biased locking piece mounted on the lower element so that the tilted upper element can be firmly fixed in a selective place with the opened canopy tilted at a desired angle, and the canopy will not be overtilted in operation as a result of the restraint of the projection block in association with the arcuate groove.