23 MECHANICAL MECHANISMS FOR POWER DRIVEN SEWING MACHINES FOR COUPLING THE POWER DRIVE SHAFT OF THE MACHINE TO THE DRIVE SHAFT FOR DRIVING THE NEEDLE ASSEMBLY OF THE MACHINE, SOLD SEPARATELY; COUPLING ASSEMBLIES FOR SEWING MACHINES FOR COUPLING THE NEEDLE DRIVING SHAFT TO THE NEEDLE ASSEMBLY, SOLD SEPARATELY; AND BRAKING ASSEMBLIES FOR SEWING MACHINES FOR BRAKING THE SHAFT FOR DRIVING THE NEEDLE ASSEMBLY