Bucket locking mechanism

Claim 1

In a turbomachine of the type including a rotatable disc formed with at least one slot extending generally axially of said disc at its periphery, a blade extending generally radially from said disc and having a root portion engaged in said axial slot and a platform portion, extending over a portion of the periphery of said disc, said axial slot and said root portion sized and formed to abut and radially lock the blade to the disc against centrifugal forces, means for axially retaining said blade root in said axial slot comprising: a locking key having a block portion and an elongated stem portion extending therefrom and terminating at a distal end; said block portion having a thickness defined by radially inwardly and outwardly facing surfaces, a width, and a length of greater extent than said width, said stem extending normally from a central position of said radially outwardly facing block surface; said platform portion formed with a circumferentially extending slot in its radially inner side, said platform slot having an axial width sized to receive the width dimension of said block in close fitting relationship thereto and having a radial height sized to receive said block in noninterfering relation with said disc, a radial opening formed through said platform portion and communicating with said platform groove for receiving said stem portion, in close fitting relationship therewith, when said block is engaged in said platform groove and for providing access to the distal end of said stem; a circumferential slot formed in the periphery of said disc adjacent said axial slot, said disc circumferential slot having an axial length sized to receive the length dimension of said block in close fitting relationship therewith, said disc circumferential slot located and having a radial depth such that when said blade is inserted into said axial disc slot, said locking block may be dropped radially out of engagement with said platform slot and into engagement with said disc peripherial slot and then rotated to axially lock the blade in the axial disc slot.