Connecting a shaft to a bore

A shaft (44,144,145) is conventionally driveably connected to a bore (46,146) by a steel key of rectangular cross-section. Where the shaft is of smaller diameter than the bore, a slotted nylon sleeve is fitted between them and a tall steel key extends through the slot. Failure of both standard and tall keys can occur for various reasons. A unitary component (50,162,163) of suitable plastics material or non-ferrous metal is therefore proposed. This component essentially includes an integral key (56,174) of curved cross-section adapted to engage in a mating keyway (176) formed in the bore. Where the shaft (44) and bore (46) are nominally of the same diameter, the component (50) consists also of an integral key (52) of rectangular cross-section adapted to engage in the conventional keyway (48) in the shaft. Where the shaft (144,145) is of smaller diameter than the bore (146), the component (162,163) also includes a sleeve (164) with the key (174) of curved cross-section formed on its outer periphery, and a keyway (170) of rectangular cross-section formed in its inner periphery and adapted to be driveably connected by a separate standard key (171) to the conventional keyway (148,149) in the shaft. The component is useful in the flange-mounting of different electric motors on off-the-shelf gear units.