Coupling between spanner and demountable socket piece

摘要

The spanner (1) has a shaft (2) connecting a handgrip (4) with a head (5). The head (5) contains a plug piece (3) and a ratchet mechanism. The plug piece (3) has an undulating outer surface with eight high and eight low regions. A socket piece (6) has a recessed end (7) with a similarly undulating inner surface to accept the plug piece (3). The hardness of the profiled areas is typically 50 to 60 Rockwell C. The recessed end (7) can also accept a standard plug piece of square cross-section. The other end (8) of the socket piece (6) is shaped to accept a specific size and type of screw or nut.