Tool for making wax patterns for casting impeller blades

摘要

The tool consists of a first set of loose parts defining the outer contours and a second set of shape-segments (5) restrained to move on a transport mechanism and then defining the vane shape of the impellers. The transport mechanism comprises coaxially assembled carrier plate, drive plate with spiral grooves radiating from the centre and acting as transportation and a curve plate rotating with the drive plate though pins which run both in the drive plate grooves and other spiral grooves in the curve plate. Each shape-segment consists of a segment foot, a vane contour form and a carrier pin which rides in the groove of the curve plate. The shape of guide plate (10) is a composite of two or more curves so that at a point (44) the sense of rotation is reversed. Each shape-segment has, in addition to its drive pin (11) an additional guide pin (12) at a distance (43) from it.